Okay, just finished my first Full Campaign with Pontus.

Here's my take.

IMHO, Pontic Light Cav is one of the best Router chasers in the game. Keeping them in reserve, then charging them after a router is great already, but they'll use their Javelins as well. This mops up those routers FAST, which is good for pontus, since they can easily rout one or two units, but the whole army's tough.

Bronze shields are decent, and they stood up to pretty much everything, with the exception of Praetorian Cohorts and Urban Cohorts.

I picked a fight early with the Selucids, which unfortunately brought me far too quickly into a protracted war with Egypt, which took half the campaign. Against Egypt, Chariot archers are your best friend. Good mobility, and in an emergency, you can charge them in to give that last little nudge into a rout. (I like the fact that they scare just as well as the Scythed...)

Cretan Archers are a MUST Recruit. Save em up, and they'll save yer ass when you're up against rome in the end-game. If you get lucky, (Like I did) and wait to take Greece, you can get them up to level three weapons if they've fully upgraded a temple of Artemis.

Tactics that seem to work well on rome are strongpont with your phalanxes, and use chariot archers/ HA's on the flanks. If you've got Onager's so much the better. I find that with Pontus you want to use similar tactics to Greece, but with more empasis on pure MOBILITY. (Since your phalanxes don't have the staying power of Greece, you want to stay on the offensive when it gets down to it.)

I managed to stay friends with rome RIght up to the point when there was only me, the Germans, and Britannia left. (I killed Egypt, the Selucids, Armenia, Parthia, and Scythia. The romans took care of everybody else.)
If you do that tactic, you'll be up against the Brutii. I found a good place to make your stand is near Campus Scythii. There's LOTS of open terrain, which gives you good maneuvering room. I killed almost all of the Roman forces there, and then just amphibious assaulted Greece and rome for the win. Whoot!

Overall, I'd say they're a fun faction to play, just because they have no major UBER units. However, they're flexible, and with some good merc recruitment, you can build them into a decent force.

One last note. I found that Pontus Heavy Cavalry was useful throughout the game. The combination of decent hitting power and minor standoff ability served me well, especially in support of Phalanxes.