the 880 and the 720 has a color screen and rechargable base and battery and it automaticly lights up when you pick it up, the 880 also has 8 custom soft keys at the top of the remote vs 6 on the 720, which can be labeled to do anything you like.
My 880 has all of the DVR speicalty buttons on it like, DVR list, On demand, day forward, day back, and I also put TV sleep and pic mode on there because I use them alot.
But the 550 with four soft keys and the 720 with 6, can do all the same thing by change pages on the remote, it is easier if every thing is on the the first page.
I own the 880 and the 659 I love them both the only problem is the 659 didnt have a page up and down on it which doesnt matter with direct TV because the page up and down is the same as Channel up and down, and I only got 4 soft keys.
As for the 880 I also had a problem with the charger base, you have to clean the connection some times and I had to take it apart one time to fix the connectors, plus it about a year old now and I think I need a new battery, its only lasting about 2 days before charging.
So I would say if you are going to have alot of people using this remote and you dont have a DVR, I would get the 550 and maybe the 659 its not a pretty looking but it has 4 buttons on top for watch TV, Watch DVD, and Listen to music and that make it a little easier for some people and the same amount of soft keys.
and if its just you and/or few adults the 880 and 720 can give you more flexablity, but everyone will have to charge it when the battery gets low, and if you can get them to put it on the charger when the battery gets low, show me how so I can get my wife to it. lol
hope this hope