underground gamer and bitgamer

[RCBH928]

I just want to know the difference between the two.
UG talks about bitgamer as they are sister site. i went to bitgamer and all I found was username and password input. Nothing more to explain.

I am member at UG, but don't mind being member at bitgamer too whatever it is.
Can some one shed some light, are they like same site with different name?

[Hatta]

UG is for retro stuff. Bitgamer is for more modern stuff. Both are excellent trackers.