i have a game buy-in theory question

[facepull]

your bankroll is 6000
your game will be 1-2 no-limit
you have a choice between two games
the first game is capped at a 300 buy-in which 6000 is plenty
the second game is uncapped
is it better to take the capped game or to buy-in into the uncapped game?
in either case you would buy in for 100bb.
the thing that bothers me about the uncapped games is that it plays much bigger then the blinds allow for. some will buy-in for 500 to 1000. 6000 bankroll does not support these matching buy-ins
please this is a honest question