I had a flight to KL earlier this week departing from T2. So thought I would provide my thoughts on the overall experience. T2 is far from complete, half the landside and airside parts are closed off. There are only a few shops at the moment airside. It was fairly quiet mid afternoon.
As for the T2 Biz lounge I had read reports about some upgrades had been done...nothing noticeable from my perspective. The buffet food and drinks offering is pretty much the same at the T3 lounge so a slight improvement to what the T2 lounge used to be, but the overall experience in the T3 lounge in terms of different seating options and ambience is light years ahead. If this is still going to be the T2 SQ lounge until T5 opens I think they really need to do an upgrade.

Cut a long story short...factor in the extra 10 mins and spend your time in T3!