I also have both as well, and a 15" MBP, iMac and an iPad..
Both of my Mini's are 10.6.7. I have no issues with either. (had to do some investigative work and some patches that weren't too difficult to get the sound to work on the Mini9) Both have been runing MacOS X since in the 10.5 days when DellEFI and other tools started coming together. Now NBI makes it very easy to get up and going with a Mini running MacOS X.
The Mini9 is great for traveling, starts up lightning quick and runs quite well. I'm pretty happy with it. The machine has the 32GB Dell SSD
in it and I also have my music/videos (itunes library) on a 16GB SD card so I don't carry that stuff on the SSD
. My only complaint is that the keyboard is too clumsy for me being a pretty good typer.
The Mini10v is also great, I have the extended battery on it and used it regularly for traveling internationally. The SD slot isn't quite as nice as the Min9 (the card sticks out), but the extra hard disk space helps alot. Doesn't start up as fast, but that's due to the disk. This one also dual-boots Windows 7, although I don't think I've run Windows on it for 6 months. The keyboard is much better, closer to full-size so I don't make nearly as many mistakes. One thing to note is that upgrading to 2GB of memory is a major chore. I think the memory was the first thing put in the box and everything else around it has to come out in order to apply the upgrade. It took me about an hour to do it. The Mini9 memory is under a removable door.
The iPad is a "consumption" device in my mind, where the Mini and MBP are "creation" devices. Paired with a small bluetooth mouse, I can work on creating documents, presentations, etc while using the Mini's, but not really the iPad. Don't get me wrong, I travel mostly with my iPad these days. But the Mini's and the MBP have their place.
As someone else said, what I'd really like is the Mini10v with the "small battery" in it and an SSD
and an extra "big" battery for traveling. Maybe some day.
Oh, I use WiFi on both, have Apple keyboard and Mighty Mouse paired via bluetooth, use the audio, use external displays, and pretty much everything that you would want to do. All backed up to an Airport Disk via TimeMachine. I've had no issues with the machines other than in the early days keeping up with Meklort's tools to install the upgrades. (but the latest versions of NBI even took care of a lot of that) The 10.6.7 upgrades went perfectly.
So, if you're not a fast touch-typer, The 9 is a great box. But if you type a lot I'd recommend the 10v only because it's not that much bigger and the keyboard is MUCH better.