If you looking for apartments in Miami Beach, there are some good places to stay.
First of all, I think the Impala is one of the nicest hotels in South Beach and it will be one of the cheapest too with rates starting around $200 a night. There are only 17 rooms however so if you would like to stay here book early. The other hotels you mentioned are also good choices but you’ll be hard pressed to find a room under $425 a night in any of them.
Another good hotel is DoubleTree Surfcomber. I have stayed there many times. It is a very solid three-star, maybe even three and a half star hotel. Before it became a DoubleTree, it was simply the Surfcomber. It still has much of the boutique charm that has made the hotels on South Beach famous.
Loews Hotel located right on the beach is a five star hotel, beautiful pool with a tiki bar, emeralds restaurant on property, lounge, oceanfront rooms with balcony and an upgrade when available. It is one block from Lincoln Road and one block the other way to Ocean Drive where all the crazy bars are. It is the nicest hotel in southbeach area if that is what you are looking for.
I can recommend The Tides hotel too! It has very large rooms with ocean view, and the Beach equipment is great. The employees are very courteous, so nothing could have been better in the SB.