We purchased the getaway package that included the snorkel equipment, floats, and bikes for our family (two adults, two kids).
SNORKEL
Being our kids (6 and 11) first time they were frustrated with how to use the equipment and as a result didn't get much use out of it. In hindsight we would have been better off getting the snorkeling gear at Costco before we left. They had a great set (that they no longer carry - seasonal) for about $35. Had we gotten this the kids would have had a chance to learn how to use it. I took about a half hour and swam out to the snorkeling area and was able to find fish and the sunken Mickey. I'm sure the kids would have really enjoyed the experience had they been able to use the equipment. Renting the equipment to share may be a problem as the fins provided are for specific sizes (mine were mens 8-10).
BIKE
Later in the day when it was "time" for the bike ride, my younger son and I were the only ones that ended up going. Overall, we found it to be fun. It was a little sandy in a couple of spots but my son could easily walk his bike the 50 feet or so to get to a more "rideable" area. I thought the bike ride would be around the entire island but found that the trail was from the family beach area to Serenity Bay and then down a unpaved path for about 3/4 mile (guess???) and then back. Disney provided a couple of rest areas with cold water along the unpaved section.
FLOATS
You could get either tubes of floats. We opted for two of each. I never used mine and my kids used theirs very little.
SUMMARY
In retrospect I wouldn't spend the money for the entire package. There's actually very little time on the island and if you have another activity planned (parasailing, etc.) it is difficult to get full use out of everything that's included. If you're going to snorkel, make sure the kids know how beforehand. Rental of a couple of tubes to share would have been fine.