Lugnut is definitely a favorite from this "series 2" release of micro-changers. I liked the character from the Animated series, and absolutely loved both of the toy figures Hasbro came out with. His mini-me looks just as sweet!
Another cool design is Hardshell, who is actually a micro version of the G1 Bombshell character. I just like how the face and the pincers at the back work together. One thing I did find a bit annoying was that the hands on this guy have the slight angle on the wrists, which means that the gun he came with doesn't sit straight against the arm unless you turn the hand upside-down.
Bulkhead is another favorite character from the Animated series. I actually preferred the character there to the current one in the Prime series, but he isn't bad there. The miniaturized version is a pretty close match, just missing the larger chest to make him a perfect match.
Perceptor was a toy I didn't get in my main Transformer collection until his re-release a little while back. I liked the figure, despite the lack of articulation back then, because he was a scientist with a shoulder cannon... that's just cool. His Kreon namesake is really well executed, getting that shoulder cannon into such a small package.
There's also Powerglide... somehow he always felt like the knock-off character in the cartoon series. The Decepticons had the fast jets, and he was a slightly under-powered glider instead. But I still like how the Kreon version came out, with the swept-back wings just like the G1 toy.
The others in the series (Blight, Arcee, Groove, Acidwing, Hoist, Vehicon, and Scourge) are awesome in their own small ways, I just don't want to fill up the blog with a long line of photos that you can find with a Google search these days. All-in-all, I really, really like these guys, and I'm keeping my fingers crossed that the line has a long and happy future ahead of it! I'll keep spending my money on 'em, they just have to keep making 'em!