well, I have a pronto tsu2000 (which I've had for a couple of years) and i just bought a 880.

The 880 is much easier to program than the pronto, much. As far as your light question you can program the 880 to not shut off unselected devices (lights) if you wish. One thing that originally made the pronto attractive to me was that you could label the buttons through the gui. Almost any universal remote can "learn" functions but the problem is remembering which button was assigned what function.

The pronto can do anything, has the advantage of being totally customizable, has a steeper learning curve to use properly, if you want to add a button to a screen its very easy to do once you are familiar with how its programmed. What I did with my pronto was find screens for a similar device (ie cable box), use those screens and then customize them for my use. Any button can be a macro. It probably took a week to get it working (much longer to get it just the way you want it though)

The 880, I haven't been able to find anything that it can't do (i've had it about a week). Doesn't have the customizable screens (i should say customized screen designs), it uses "activities" (macros) as the main function. setup was extremely easy and fast (it was working within 1/2 hour). You can add functions (custom buttons with the proper labels) easily. Its smart enough to know if you add a function to the tv (i have one setup for tv w/stereo and one with the tv speakers) it will add the function to all activities that include the tv. You can also control the individual devices on the system as well. an example would be the tv w/stereo, turns on the cable box, turns on the tv, turns on the stereo, puts the tv on video 4, stereo on tv input, and shuts off the tv speakers. When I switch activities it turns the tv speakers back on. When I hit the off button, everything turns off. If I switch from tv w/stereo to just tv. the remote turns off the stereo and turns on the tv speakers, without turning off the tv or the cable box.

Sorry if this rambles a little, I've tried to answer your questions. I would suggest going to the logitech site and it allows you to setup a "test drive", you can see how easy it is to setup.

I've currently got a sony rear projection 1080p, a hd pvr cable box, dvd, and surround sound system.

The 880 can handle extra rooms with no problem, just have different activities for each room. The activites can be custom labled, as can any special buttons you want to add.