Humbolt,
Took the family of 5 to Palau last spring break and we had a blast. We stayed at the crew hotel PPR (actually the only "resort" that I saw on the islands) and I thought they charged fair, around $250 a night with taxes and fees etc plus food. We did three dive days and my wife and son did two snorkel/kayak tour days and they had a blast on their trips, saw lots of stuff with snorkel that we saw diving.
Don't know if you have kids or not, but they also had a dolphin interactive area that was fun as you could swim with the dolphin etc and it was very inexpensive for airline id'd people. (kids loved it).
Now if you wanted to save more money, the hotel up the hill from the PPR had access to all of PPR's beach and amenities but was much more hotelish and less resortish, and I believe their rooms were about 1/2 price compared to PPR. We actually ate dinner up there one night as they had a Korean BBQ dinner buffet that was awesome for $20 a head with everything included.
It depends on what you want to see with snorkeling, as Guam will have clear water usually, but much less life to see. On that trip we ZED'd back from Palau to Guam and stayed on the Navy base for 3 days and did some diving there too.
I've snorkled/dove all over Hawaii, parts of Guam, and Palau and for seeing very interesting and unique things in the ocean, Palau wins hands down.
BTW all the locals speak english and currency is US$, no visa needed.
LUV