I have the Onkyo 876, which is a close approximation of the 886.
In addition to the fact that the 876 is a receiver and the 886 is a pre-pro, some differences include
- lack of 12V trigger versatility on the 876
- no balanced pre-outs on the 876
- slightly less capabile zone control
- uhhh... some other minor stuff?
I haven't been paying too close attention to the replacement of the 876/886 coming out (avoiding upgradeitis), but at least one thing I was told the 887 will include is independent subwoofer MultiEQ-XT calibration for two subwoofers. Unfortunately that's something that I really could have used with my setup, so I'm biting the bullet and getting an external solution for the same purpose.
Anyway, this is one of the best values in a home theater pre-pro out today. It's excellent at all digital audio formats and has some of the best video processing available in this pricerange (although you said you wouldn't be using it). I'm not really familiar with the Rotel for a comparison, but the 886 (and the twin Integra 9.9 pre-pro) are basically the reference pre-pro units in the $1500-$2500 range that others would be compared against. The features they have are extensive and they have some of the best sound quality available from digital sources.
The fact that it has MultiEQ-XT should be a big jump in performance if your room is causing any issues with your sound now. If I was going to replace an aging pre-pro now (and I wasn't in the dual subwoofer situation I am now), I'd strongly consider the refurb 886 option.
I was able to snag my refurb 876 for a couple hundred under the $900 mark from Accessories4Less and I've been quite happy with it.
EDIT: Oh, and is it old technology? No.
EDIT2: Ok, here's the new lineup of Onkyo receivers and what they have that's new over last years. The 886 replacement should be similar to these.
http://www.audioholics.com/rev...ke-aim-on-the-internet