Comparing manual trans options - variables other than gear ratios?

Aside from gear ratios, I don't see a lot of comparison between the possible transmissions in terms of other variables. Did any other factors impact your decision? How did you pick yours? Would you change it if you could? Any regrets?

These are transmission options that I see tossed around the most:

A833
A833 aluminum case (and overdriven 4th?)
A855 (Passon Perforance 5 spd)
TKO
TKX
T56
T6060(?) Viper, etc.
Others?

If we put aside the number of gears and their ratios, which ones compare favorably or unfavorably for the following variables (or anything else that I didn't think of):

Strength
Longevity/durability
Parts availability
Cost to purchase
Complexity of installation
Mass
Driveline energy loss
Noise
Driving experience/shifter feel/clutch engagement
Unique problems??