I'm at level 18 now (10 wiz/8 monk) and it plays okay. He's certainly not optimized and anytime there's another caster around doing haste/rage, I'm basically just a subpar monk.
Basic summary:
Decent melee damage with TWF line and stat placement similar to a str/con monk.
Passable quest tank that can get a decent AC, plus has shadowfade (I went dark path) and can self displace/self cloud
Low-to-Mid hps - 350 at level 18 - lichform will help to rectify this a bit. 450'ish capped
Low BAB - DP clickies required later on if you want to hit anything.
Ultimately, it's a gimmick toon. You'd have a stronger character as either pure monk or pure wiz. Even going 11 wiz/9 monk for ToD would be a DPS improvment.
What I'm really hoping, and what would be a significant improvement for this toon, would be if Tenser's gets a little love when they look at spells. Currently, a level 6 Arcane spell is completely inferior to a Level 3 Divine spell. Primarily it's because the stat bonuses don't stack with items. If they changed Tenser's to have the same stat bonus "type" as lichform stat boosts, I'd be ecstatic. The Favored Soul "Bladesworn Transformation" is pretty much exactly what Tenser's Transformation *should* have been.