I stayed at Le Meridien in St Julians a few years ago. I was there for a conference, so I didn't actually choose it... but I thought that our conference organisers had made quite a good choice. Nice hotel, good facilities, and a superb view if you were lucky enough to have a sea-facing room. Also, it's very central, with a good choice of restaurants nearby.

Got nothing to compare it with (as it's the only time I ever stayed in Malta) but would certainly stay there again.