Simple question,

For me my favourite is easily the archer/sniper. I haven't played awakening or fates but prior to that and even now all I do is favour archers to the point where they usually promote faster than everyone else.

My least favourite would have to be the warrior. I don't mine axe units much, but I'll take a lovely beserker over a warrior anyday. They just seem.... boring to me.

Kinda a FE noob, but probably Archers are my least fav.

They destroy Pegasus Knights, but other than thay, I feel like they are just outclassed by magic users.

Not sure who my fav unit is, I guess Pegasus Knights cause they can move around a lot.

Favorite is easily mages, I don't know but I just use them the most. The benefit of 1-2 range is quite nice.

Least favorite is definitely a tank class like knights. I just hate using them

I don't exactly like them that much, but their crazy defense makes them enjoyable somewhat for me..

Paladins are the best. Nothing like being a mounted knight that destroys the enemy and has also an extra movement if you haven't consumed it all.

I guess my least favourite...hmmmm...I'm tempted to say Lords, but mostly because of how bad some Lords are, both as unit and personality-wise.

Roy? And I agree with Paladins being the best, I loved them before I fell in love with archers

Favorite definitely depends from game to game. Sorcerers, for example, are extremely good in Awakening, perhaps even broken, but in Fates they're really bad. Huge (and needed) nerfs to their def and nosferatu are largely to blame for that. I guess if I had to pick one throughout the entire series, I'd say that Great Lord has always appealed to me and has consistently been good.

Least favorite is definitely knight/general. Too immobile and resistance sucks.

Wyvern Riders/Lords is my favorite because they're bulky, strong, and have high movement and General/Knight is my least favorite because of the limited movement.

Wyvern Riders, Great Knights, Sages and Swordmasters are my favs.

Warriors, Snipers and Bow Knight are my least fav.
And Troubadors... and Pegasus Knights... and Dancers...

Was never fond of Eirika, Ephraim, Marth (to an extent), Chrom and Micaiah (pre-Interesting Plot Details). They felt like really plain characters, though some were competent in combat.

Never played Roy's game, but Elliwood, Hector and Lyn are an awesome trio of Lords.