Just added Rilgon's blog, Stabilized Effort Scope, to my blogroll. He's apparently a dedicated Marks Hunter from what he's told me, which is interesting.
I haven't run pure Marks myself for a while now, but I was using 0/31/30 for a period of time before I broke 600 ag; TSA gives more AP up until that point, and truthfully with RWS I'd probably still be doing more damage with a heavier Marks build even now.
I did, however use a more or less straight Marks build for a while in HFP, at probably around level 62 or thereabouts. It doesn't have anywhere near the melee viability of Survival, of course, but at the time anyway my ranged damage was considerably higher with it, also...so it balanced out. It's a very solid farming tree, but I did find mana efficiency to be a minor issue, and given that that has also been reported by people in raid scenarios, I'd be interested to hear how Rilgon manages to cope with the mana problem.
Probably the single main thing I enjoyed about Marks was that, given that it is a lot more Hunter centric than BM, I could focus on personal damage output, and still have the pet primarily for defense.
Marks could do with some attention from Blizzard, IMHO. Efficiency could use bumping up to around 30%. TSA also needs to scale, a la EW; scaling with Int would make the most sense, since CA already does. I'd also tweak Barrage and friends so that they buff Arcane as well as Multi; since currently if CC is around, due to no Multi, a Marks Hunter has to go without a fair portion of their damage output.
CA, RWS, Master Marks, and TSA are all still as sexy as they've always been, though; if Blizz made the above changes and also put Resourcefulness higher up in the Surv tree than it is currently, I'd definitely consider going a bit deeper into Marks than I traditionally do currently.