Pony quality.

[Greylady]

Also, Rarity gets dirty amazingly easily. I washed her with soap and water, yet the marks still won't come off.    I'm not even sure how they got there. At first I thought my hands were dirty, but I'm a bit of an obsessive hand washer, so how could that be? The other white ponies aren't as bad, probably because Rarity was my first pony toy.

Well, white ponies from every generation tend to look dirtier in my semi-well-versed-in-different gens experience, sadly. I have five G4 Raritys and they tend to look dirtier quicker than the rest. If the stains are bad enough you may want to try a little acetone or magic eraser being very, very careful of eyes and symbols. The playful pony G4's are so frightfully small that's it's hard to avoid them, however. >.> When in doubt, I leave stains and just try and style the hair as best I can to hide them. Curls and legs wraps work a treat at disguising flaws.  Especially on G4's with their tiny bodies.

My latest Rarity is the lifted front leg one that comes with the carousel boutique and she has a sliver of the pink plastic used in her saddle stuck under the glue of her glitter symbol.  Some of the glitter also seems to have snuck into her eye paint, but that's not too bad and makes her have a nice twinkle in her eyes.  She also has a lot of dents in her lifted leg. Has anyone experienced such dents in their ponies with lifted legs like Sweetie Swirl and Cheerilee? I believe it's a flaw with the mold as the Sweetie Swirl that also came with the set has similar dents.

[Watercolors]

In general, FS are higher quality than the brushables, but my sister's FS pinkie pie did have a few issues. She has a few scuffs on her head, parts of her were pretty sticky, and she had a big, black line on the back of her head.
And, after owning quite a few brushables, I've found that just about all of them have small issues. Twilight toys almost always have mismatching heads and bodies, Snowcatcher has mismatched eyes, and Diamond Rose has a cutie mark smudge. When i got Lulu Luck the other day, there were only two left. The one I didn't get had dirt on her face! it was pretty gross. The one i did get, however, has a misplaced cutiemark 
Fluttershy and Cherry Pie my only flawless ones.

[HollowZero]

I have Lulu Luck, Blossomforth, Twilight Sparkle, and Valentine's Pinkie opened.

Twilight definitely has mismatched head and body color, and Blossomforth isn't really "white", she's more of a very light gray. Kind of how G3 Coconut Grove was. Their hair has always been fantastic though.

[InkyMilk]

Perhaps I am just extremely lucky, but I can't find anything wrong with any of my G4 ponies. But then again, aside from my Blind Bag ponies, I only own four of them, Rarity, Fluttershy, AppleJack and Ploomette. I just inspected all of them over again in detail and there aren't any mismatched heads/bodies, rubbed off cutie marks or excess glue. The only problem I noticed was that AppleJack has the tiniest of scratches on her eye which I had to really study to notice, but that very well could have been my own fault as I wasn't the most careful with storing away my ponies when I moved a month ago.

I would still like to get the other three of the mane 6, along with a few others, so I'll certainly be more aware when it comes to quality control issues and whatnot. I dunno, I never really looked too close at them when I bought them and they're all quite pretty to me!

[keylimepony]

The FS ponies are great! I was on the fence about getting Pinkie but I am so happy I did. I've looked her over and I don't see any flaws. I think the FS are fabulous! Plus it helped that Target had a Pinkie Pie herd for ages and the price dropped by a few dollars so I took that as a sign and brought her home. She makes me smile.

I also have a Bumblesweet and my only complaint with her is that I wish her tail was a tiny bit fuller. Well that and how much of a fight it was to get her safely out of the packaging. There are a few more I have my eyes on (Lyra, Plumsweet) but I'm content to wait for a little while. Plus I wish the cutie marks were on both sides but that probably won't change.

[Flutterblossom]

Overall, 95% of the g4's I've purchased have had no issues with quality control. The one pony that I did have an issue with, Diamond Rose, came with a tail that had a strand of hair twice as long as normal and the rest half as long. I did end up cutting it to be short, but she's still very cute and it's not that noticeable. Oh yeah, and their hair is REALLY soft! 

[Rion]

Most of my ponies don't have very noticeable issues, but there's definitely an amount of them with something you can spot easily. The mis-matched head/body color is the most prominent issue, along with the occasional glue glob stuck to a various part of my pony's body.

The worst one though is my Cherilee, which has what looks like a blob of dirt on her eye- the worst part is that it won't come off!

[LadyMoondancer]

I am really disappointed by the quality of the brushables, specifically the very obvious seam in the plastic, particularly going up their front legs and over their chests.

It's really shoddy looking and is present on literally every small brushable.  (Not on the larger Fashion Styling ponies, however.)   Also by the stubby unicorn horns on the small brushables (again, not on the Fashion Styling ponies).   The adult unicorns have the exact same length horn as the baby unicorns.  I am pretty sure their ears are longer than their horns.

[xoVanille]

Only issues I've had are very slight color mismatches, which is bound to happen and wasn't that noticeable in my case, and sort of tangled hair.

These ponies have awful box hair most times but it's easily solved with some hot water and a pair of salon shears to cut away strays.

I haven't had any symbol scratches (knock on wood) or anything of that nature, no googly eyes or whatever. Though, Luna's eyes creep me out...o.o All of that being said, I enjoy collecting them because I think they are good quality for what you pay. (: That's just my opinion though. I've got over 50 ponies...and have had no major issues.

[Appleseed]

I have not had any major issues with my G4 purchases. My herd currently contains 13 ponies and the only issues I've managed to detect:

- My Applejack has a random bit of glue stuck to the back of her head that I'm scared to peel off, also a little "dirt" mark on one of her ears;
- My Feathermay (which I just got at Wal-Mart today) has a slightly cracked/disfigured tail hole, with a strange indentation around the lower part of her back above it;
- Feathermay is also the only pony I have with the head/body color mismatch issue but I believe this is a problem all Feathermays have. My Twilight has it a tiny bit but it's very subtle, not noticeable unless held up to light.

That's all I can think of for now.

[Dibbles]

I've been pretty lucky, but I still have a few ponies with slight head-body mismatch and with dirt spots. I also had to wash glue chunks out of my Twinkleshine's hair. But overall my experience with G4s has been good.