I started a inexperienced infiltrator some time ago. Played him from 17 to 21 (right now), and have found it neat. I haven't sat and farmed experience at the academy. He's traveled around a few continents, battled enough to gain honor/prestige, and had a few successes. Both swordfighting and infiltration is at around 30-40%, wounded one and was caught on my second attempt at a higher profile target. Might have been caught a few times for stealing and/or various mischief, but no bans that have stuck.
As long as you hold back some gold for training at the academy while you refit your troops, you'll make some progress. Much more of a gambler's class.
Poll