Hello Rwhitting, I've been to Tufi a couple of times and Milne Bay a couple of times, but not to Tawali specificly. The diving in both is great. One difference will probably be the length of the boat rides, I'd bet that there are more sites closer to Tawali than Tufi. But, you might get a little more big stuff on the outer barrier reefs/sea mounts of Tufi and the viz will probably be a little better than MB. The big stuff in MB is on seamounts that can be a ways out, I'm not sure how far Tawali's boats go. Also there will probably be a bit more critter action in MB. But there's critters everywhere in PNG, if you know where to look. Right of the Tufi dock we found lots of critters-Mandarin fish, pipe fish, Flambouyant Cuttle fish, can't remember them all. Hard choice, but the weather may make it for you, as the wind at Tufi can be very strong whereas MB has lots of shelter. Thre may be a way to dive the Blackjack B-17 wreck from Tufi, an amazing dive, well worth doing. Get the Lonely Planet Guide, it has detailed weather info. Happy trails -Andy