Coming from an older SL-8000 Home theater master URC remote, I went to the 550. It's not that great folks. It's purdy, but it's super slow at sending commands (my biggest complaint)and the entire thing is designed upside down. Its the only way I can describe it. And I'm not sold on the activity idea just yet. I think I like URC's hard buttons/pass through combinations better. Then there's the "click". Everything bloody clicks. Volume up/dwn, channel up/dwn, ok button and more. click click click.....ARRRRG.
Setup was painfully slow. Yeah it's web based, but I still find it very tedious, and it has troubles learning commands from some other remotes in the house, i.e xbox, infocus etc. I hated having to setup the device and each button, then repeating that same task in the blessed activity again.
Overall I'm going to keep it, but it's not a "keep forever" type remote. And I feel one drop on the floor, and it'll be dead.
Why do I say upside down? Well, the number keys are in the wrong spot, and too small. The menu/info/guide//up and down arrow/exit buttons are too big ( actually take up the same space all 10 number buttons do!!?!!). The play/ff/rw etc buttons are in the wrong spot and are all the same shape. Spongy feel to some buttons. The list goes on. Then there's the shape. With the batteries on the bottom backside, you hold them in your hand all of the time. It's the widest part of the remote. Anyone that owns it, do this, take the remote, hold it upside down so that the skinny part is in your hand. That feels better to me. Also, when sitting on a table, the IR sensor points down rendering it useless, when it should point upwards at your equipment.
It lights up very nice, it is light, battery life seems good. Works with the next gen ir-rf products, the help button is handy as is the new a/b buttons not found on the 520. I would like more control over arranging activites and devices as well as a clock on the darn thing ( something nobody every thinks of). The glow button is very handy....also clicks

See, I do like it, but it's not as good as the remote it replaced and which lasted a good 8 years.