First impressions are good - the build quality isn't as bad as I expected. It feels a bit cheap, there's a bulge where the chip is, the spring mechanism doesn't feel great and the sticker's on wonky, but the way some people were talking about it it sounded like if you looked at it the wrong way it'd fall apart when it's actually fine.
The interface is great, although it takes a bit longer from turning on to having a game running than my R4. Skinning is excellent but I've not really settled on one skin yet - possibly because it's more complex than R4 skinning most skins I like the look of have something which bugs me about them, like a colour scheme that makes it hard to read, or badly aligned highlighting. Every game I've tried runs fine with no slowdown.