I am ok with Thaco since I play 1e and use the 2e Thaco chart anyway.

For us Thaco is just as fast as the 3e way of doing things but we don't give out ACs. We just roll and tell them DM what we hit. Its fast.
ACKS doesn't use THAC0 the same way 2e does, so you'd have to convert or learn the new system. An unarmored character in ACKS has an AC of 0, and the character classes are given a Target Number to hit that AC of 0 (TNAC0?). The target number varies by class and level. AC ascends, as per 3e, so an AC of 7 is plate mail (or plate and shield, I forget). You can convert it into a 3e to hit system by adding 10 to all the ACs, and changing the target number into a bonus.
Different people have different preferences. I'm aware of that. I am terrible with numbers; it took me three years to remember my zip code after I moved. Memorizing a table is right out, as is some equation that intersects class, level, and AC.
(And for what it's worth, I used THAC0 all through 2e. I'm intimately familiar with it. I was also deliriously happy to switch to ascending AC and To-Hit rolls, courtesy of Unearthed Arcania.)
The ACKS system does, in fact, require a different target number almost every roll, since different characters will have different target numbers to hit the same creature, particularly at higher levels.
I believe, personally, that the fundamental question to be answered in D&D combat is "do I hit?", and the 3e to-hit system provides the simplest answer: AC = target number. In ACKS, AC does NOT equal target number; you also need to know the attackers target number (or class and level), so my question to Tav is purposely a trick one, and cannot be answered (unless I'm severely misunderstanding the ACKS attack system, which is possible.)