Well, I just bought a 900 to replace my still-working 5-year old 890. I've configured the 900, but haven't tested it yet. (Tonight, perhaps.)
I purchased a Harmony One two months ago to replace an 880 I spilled a soda on.
The differences will be mostly using one hand or two to control your system. I have not used a 1000 or 1100, so I can't say how much of a difference that makes.
I really liked the 880/890, so I wasn't sure how the new style would be, but I quite like it. (So much so, I picked up a pair of similarly styled 700's for the bedroom and kid's room.)
It takes just a few minutes to get your devices set up. (I recommend you glance through the appropriate threads for tips.) It takes considerably longer to dial your configuration in. I've found it helps greatly to write everything down on a sheet of paper before using the software. For example, in my theater I have 7 devices; Projector, AVR, Media Streamer, Laserdisc Player, Scaler, Lights, and Curtains. When you set up activities, such as "Watch Movie", you'll need to know what state your devices need to be in, such as "AVR set to DVD".
For consistency, I set up my additional soft buttons to be the same in all activities. In my case, the second page of soft buttons on all my activities are for lighting.
I will miss the sequences, or macros as everyone else calls them, that are on my older 890, but not on the newer 900. Currently I have a sequence called "Pause Movie", which pauses the movie and brings up the lights with one button press. It will be two with the 900.
As I haven't set up the RF for the 900 yet I can't comment. The older 890 had stick-on emitters and 3.5 mm jacks. The newer 900 uses mini-blasters (small IR repeaters) instead, and 2.5 mm jacks. I don't know the particulars of the 1100. I know it doesn't ship with an RF-to-IR base station, but I'm not sure which ones it's compatible with.
I hope I don't come off like a Harmony fanboy - I'm not. I think they shouldn't have dropped sequences. Also, I could rarely get the charger to work for any of my 8xx remotes.
Now the Philips is out of the market, perhaps URC might be an alternative. I have no experience with them, however.
Hope this helps. Let us know what you decide.