bit depth - 6 vs 8 vs 10+

how much does this really matter for photo editing/color accuracy?

bit of background:
currently use a 13" macbook to edit my photos, and am looking for an external monitor for this purpose instead
was looking at the Asus PA248Q based on reviews, which has an 8bit panel, but then also stumbled onto the older PA246Q monitor with 10bit depth and the newer PA249Q monitor that also has 10bit but is considered wide gamut

i dont do any printing, but would definitely like more color accuracy. haven't seen many hits for these monitors in searching POTN, so trying to gather more info from more seasoned folks

Have a read of www.tftcentral.co.uk their reviews are excellent. Just about any monitor's fine when calibrated. Jpegs are 8 bit and they look fine, I wouldn't go for 6 bit and 10 bit is probably just a tiny bit better than 8 I guess.

I wouldn't worry about needing 10 bit per channel color. I'm not even certain if even the newest MacBooks support it anyway. Only certain high end "pro" graphics cards, usually ones designed for CAD workstations, support 10 bits per channel.

About the only advantage of 30 bit IMO is having less banding, which is likely only going to be a noticeable improvement if you edit in ProPhoto RGB. IMO its a lot of investment to enable such a small improvement, so I haven't bothered.

My advice would be to pick a decent quality IPS monitor that is known to calibrate well and has good corner to corner uniformity. Don't worry about bit depth or contrast ratio.