Just in, since my new charger is just sitting there I decided to do some 5A discharge tests. Not that many people are going to push these cells quite so hard. I figured it would be fun to see what they can do. 2.8v cutoff
XTAR 2600 = Connection brake at 13 min (i'm guessing the PCB kicked in probably not a bad thing really)
HI-MAX 2600 = 2273mah
In all my testing the HI-MAX has been 100-200mah higher than the Xtar 2600's.
XTAR 2600 Resistance = 136 mOhms
HI-MAX 2600 Resistance = 162 mOhms
It seems the case that XTAR sanyo based goes around 24xx mAh consistently. Capacity wise one could easily ask 150mA more out of them but it does perform equally as "vanilla" sanyo battery. It is a very decent battery but the lack of a few (debatable) mAh does not really warrant a "true" 2600 mAh marking. I like em tho. Can't beat price/quality if you consider sanyo is a very known HQ manufacturer.
No1 knows what hi-max are made from and how well will they do after several cycles. I think both are great options. I would choose either one but would prefer XTAR if similarly priced.