while im not so in love with some of the sets robot modes due to shoulder and limb placements or the smaller sets lack of knee joints...i have to say i friggin LOVE building these guys.
its also nice that you have the option to rearrange anything you do like on a particular set since its just building blocks. thats makes one of my major complaints almost a none issue right there.
last night i managed to "fill out" my optimus trailer to a full one using the left overs from my second optimus set and change up some things that really bothered me about optimus himself.
i hope series 2 comes bringing some new piece designs.
my least favorite so far has to be prowl...horrible chest and wtf is up with where they decided to put his shoulders at? his kreon is his only saving grace. honorable mention goes to mirage AND jazz for lack of articulation thanks to having no knees or hands. i still like them but it would be nice to be able to do something else with them rather then have them just stand there