Hello, I thought I would chime in since I got the HK 235 a little over a week ago. I also demoed an HK 630, HK DPR 1001, and a Yamaha 5790 in the last month. I do not have a lot experience and I am not very technical, but I will try to give you some useful insight. To start off with, I am currently running 5.1, Cambridge Tower IIs for mains, centerstage, and 5.1 surrounds. The mains are 6 ohm nominal, not sure what minimum is. I also have been unable to find their sensitivity rating. The manual doesn't even list the specs. This is currently my main listening/viewing area for now. That will change in the near future, but I plan on leaving the 235 at its current location and getting a new receiver for the new location, so my requirements for the 235 are pretty low.
Anyway, setup for the 235 was pretty easy, the OSD is pretty generic but easy enough to get through. I did have a remote from a previous model that had an SPL meter built in, so I used that to adjust the speakers. The 235 does have EZSet, which seemed to work ok, but it just levels out the speakers so I did it manually anyway. Assigning inputs is also pretty easy thru the OSD. The only problem I may have, which I haven't been able to verify, is that when watching Master and Commander with DTS, the speaker levels were not set. I swear I had set them previously for DTS, but maybe not. Since I set them (again?) I have not had them default yet (again?). When you set up the system, it can use the same settings for all sound formats when it comes to speaker size, cross over, etc. However, you will need to adjust the speaker level for each sound format you use on each input, a bit tedious but not too bad.
I will leave the sound of the receiver up to you to decide on and assume you are able to demo the receivers you are considering so you know what you/he like. For performance with cds and stereo, it was putting out around 80db in the lower -20s. For me that was more than adequate and louder than I would need it even if I wanted to crank it or was in different part of the house (I am assuming the SPL meter in the remote was accurate, which it may or may not be, but it wouldn't read over 80db). The room it is in is 15'x'16'x9', with the back wall nonexistant and open into the dining room and kitchen. I did push the receiver some (only once) to about -10db, which to me was unbearable (I was standing 20-25' feet away from the speakers), I had it there for about 30 seconds and then started turning it down. The receiver then when into "Protect" mode and shutdown. I was able to power it back on immediately and start using it again, but I am not sure what caused that. If it was my speakers, the enclosed cabinet making the receiver too warm (backside is open), or something else. If anyone has any thoughts on it let me know, I plan on trying it again tonight with the door open for more air circulation. But since it shutdown on volumes that I would never listen to I am currently not concerned about it, though I am curious why it did it. The receiver runs warm to the touch, but never got as hot as my old Pioneer or the Yamaha I tried. It does have a fan inside according to the manual that will kick in as it heats up. I haven't heard it, so I am not sure if it is quiet or just hasn't turned on yet.
With movies the receiver performed quiet well, M and C is a great movie to watch for the soundtrack, and good movie in general. For some of the battle scenes I kept the volume around -15, louder than I would normally listen to it at but I wanted to push it a bit and it handled that fine, no Protect modes kicking in. The receiver works fine with detecting the signal. It does 7.1, and I know some people have complained about older HKs defaulting out of 7.1 when switching channels or sources, but since I don't have that many speakers I was not able to test it. It has a couple of DSP settings which I do not bother with. It also has bass and treble adjustments on the front of the receiver if you need them.
I would have liked to have tried a Pioneer 1014, but the HK was a good $50+ cheaper and I was driven by price. I guess to sum up my experience with the 235 so far:
Pros
Good power for the price range
Sturdy construction on interior components
Easy to set up
Plenty of connections (4 digital on back, 2 on front if needed, 2 component)
All of the latest surround formats
Cons
Lacks Auto EQ
Remote leaves some to be desired (now using a universal learning instead)
Lacks some features you may find in other Brands at this price
All in all, if you like HK's sound and are looking for a receiver on a budget and do not require all the bells and whistles that may go unused (DSP's, component upconversion, etc) then the 235 is a great receiver.