We had an excellent stay at the Radisson. It's the most family-friendly option on the beach at this price point. Our room was large & immaculate, the pool area is fantastic and filled with kids, you can order food & drinks to have by the pool, beach access is great (chairs & umbrellas on the beach are included), and the restaurant at the hotel provides an easy option for dinner when you don't have the energy to go out (but of course there are a million other evening options close by as well - you can walk to the Fontainebleu or it's an easy & cheap cab ride to go 20-30 blocks south if you want a lively scene). It's also an easy walk to 41st St (the main drag for residents in mid-beach with many shops).
The best parts: very family friendly, large heated pool (key for winter trips!), everything is immaculate, convenient location
If I had to nitpick about something: Because it is an old pool, it is quite deep (many people are used to modern pools with large shallow ends). This pool starts at 3ft and gets deep quickly (up to 9ft). Our son is 5 and can swim on his own but not long distances, so the depth wasn't ideal. That said, there are large step areas in 2 corners that he used as a home base, and we grabbed a couple pool noodles and an inner tube from Walgreens on 41st to help him explore more of the pool. I saw other reviews about the condition of the pool which after visiting I can say are completely unfounded. The pool is in excellent shape, very well heated, just deep.