We got great advice for the Hilton from cpjones: Reserve a palapa as far away from Bugaloe as you can go. We did this a few days and had no umbrellas in front of us even with cruise ships in.
That is the only area I would pay for front row. If nothing is available there, we would pay to reserve 2nd row or further back because of the umbrella issue.
Our biggest disappointment when it came to water sports and umbrella rentals was at the Surf Club. But at the end of our stay we ended up renting an umbrella as it was the easiest way to get front row.
Some of their palapas are directly behind vendors and it shows on their map when you are signing up. My advice, stay away, it is far from relaxing in those spots.
We had a similar spot at Holiday Inn, directly behind a vendor, and we ended up switching to be further back just to get away from it.