In my Getai campaign:

MVPs:

Drapanai - These guys'll plow armored units over when given some heavier support (i.e. these guys are the best damned flankers). They'll take on most light and medium infantries, and you can pay them in pork. Their problems are missiles and being left to hold off anything alone, but they're remarkably useful.

Komatai Epilektoi: These guys are beasts, and they'll also accept pork as payment. Their stats are godly for the price (I've heard it's a mistake, so if it is I'll make damned good use of it before 1.1), and that's pretty much it for them. They may be technically skirmishers, but they'll do anything you'd normally do with heavy swordsmen.

Thraikioi Romphaiaphoroi - You all know why these are on here. Worth every penny of their affordable price. They'll plow through most anything with minimal losses, and they look really cool.

Bosphoroi Toxotai and Scythian Foot Archers - Ditto with the OP. Cheap and good, just how I like it. Oh, and hardy.

Iosatae - We all know.

Hoplitai - Very good infantry for a moderate price. I send these guys with the drapanai to do flankings.

Thraikioi Doryphoroi - These guys are amazing. Cheap, reliable, and good. You get 240 of them for a fair price, and they'll perform any medium infantry task you should like to give them. They'll fill holes in the line, protect your flanks, provide spear protection for missiles, garrison cities, etc. A good all-round unit.

Costobocii Axemen - Their stats aren't that impressive, and neither is their price, but they never cease to make me proud. I can use these guys for anything; they'll take on cavalry, duke it out with infantry, flank, chop any stray unit that may have tried to flank you, storm walls, storm gates, etc. Mine are all silver-chevron now because I love them so much, even with seemingly superior options.

LVPs:

Dacian Heavy Phalanx: Less bang for the buck than the light phalanx. You get I think one point extra in both defense and attack for a handsome price. There may be hidden stats in there to justify it, but I've ditched both phalanxes by now anyway.

Thraikioi Peltastai - Now pretty much useless with komatai epilektoi on the cheap.

Komatai - (See: Thraikioi Peltastai)

And that's it.

Has anyone used the Scythian Axemen to any extent? I have them readily available, but I've avoided them because of their stats and I wish to know if they're hiding something or if they really are just light infantry with axes.