We first fell in the love with the Beneteau 331, but when the 343 came out we found it even more comfortable and roomy. It offered us everything we were looking for in a long term boat. We've had her since 7/05 and we are extremely happy.
The plus' for buying new, for us, were 1)we have about 15 years of sailing in us (age wise) so we don't have to deal with trading in for a boat we really want in several years, and 2) this is our first boat, and we really wanted to start out with a boat that we could get to know inside and out without having to deal with prior owner, old boat headaches (we have enough of that with our old house). It's a matter of making a list of the pro's and con's, and deciding what's important for you.
There is a Beneteau 343 group at Yahoo that we invite you to join (one of our members is from Singapore).
Good luck with your decision!