do i loose all those xp points and do i gain the benefits of whatever new cc i join.
CC XPs are your contribution to the CC and they stay with the CC. In any new CC, your record would start with zero.
But, for many mid to high level CCs, these point should not matter, because there ain't no real benefit connected.
You will take your earnings from the old CC's earnings to the new one, but that ain't important either.
There are a lot of pros in an active CC, and the cons lie only in the inactive CC. Make new friends, chat and play in a friendly&reliable environment etc.
My two points: Besides of checking the members list, ask the owner on his wall before applying - his activities are crucial!