Gonna add some stuff anyway:
I know Foogly discussed ambush ranks with you. If you think you want to aim the claid sometimes, for instant headshot deaths or to leg some buggers (both of which I found useful, as I didn't care about 3 more secs RT for an instant death), you really need 25 to 30 ranks of ambush. After that you hit a plateauing effect though.
I don't remember the exact numbers but lets say that at 30 ranks of ambush you have a 70% accuracy rating with a claidhmore, well to get to 75%, you'd need soemthing like 90 ranks. It's just not worth the investment. I did the calculations with fixskills, I just can't find my spreadsheet.
So yeah, 30 ranks of ambush is all a twohander ever needs to open ambush well. You'll peak at say 65-70% with a claid and like 85ish% with a maul. You have a decent shot at hitting what you mean to, and even when you miss it's devastating.
One last thing:
Do not underestimate the power of a maul vs claidhmore. While claidhmores are superior by virtue of their weighting only, the maul is the most amazing all purpose weapon in the game in my opinion. They are light, fast, and have the best Damage Factor against just about anything you'll care about besides a lance (which is heavy and slow, and a polearm).
a 4x blessable maul is so good, that it's still worth using at cap as a weapon against any creature in the game. I can mstrike kill a troll king, a spectral triton defender, a water elemental...in one hit (three hits from the mstrike) with a maul. The damage factor is just that awesome.