Proceed AMP-2 vs BPA-2 / HPA-2

What are the sonic differences between the AMP series and the BPA/HPA series? I've read the AMP series can be a little dryer, but I read that quoting someone who was quoting someone so it's 4th hand information. Does anyone have any real world comparison experience?

I recently acquired a Proceed PAV for a new budget dedicated 2 channel reference (for me) system I am putting together.

In the next couple of months I am going to add a new amplifier. This new amp will drive NHT 2.5i's. I guess you could say I am putting together a mid 90s vintage system. I fell in love with Proceed gear looking at ads and reviews back in HS and College but it was obviously out of my league. I was reading recently about how the old Proceed HT gear is a great bargain for 2 channel listening as well. A PAV popped up in a local craigslist ad and I pounced on it. A few days later the NHT speakers came up (an extremely rare case of WAF with regards to towers).

I am coming from an Arcam A80 integrated which will remain with my HT/2 channel set up. Eventually, once I've transitioned everything, the sources will be: rega p2/goldring 1042/grado ph-1 and an appleTV with either a Cambridge DACMagic or a Bel Canto DAC 1.5.

All that being said, I really want to stay in the Proceed family (unfortunately as an architect, aesthetics are a major deal to me) to match my PAV. Also I'd like to stay within the $500-$600 budget which seems like is the price range for an AMP2 or BPA2. However, I've read great things about the HPA2.

My basic questions are: 1)which is the best amp for my system? What are the sonic differences between the AMP series and the BPA/HPA series?

I suppose if I went outside the Proceed family, I would be interested in MAC amps or Bel Canto, but that is neither here nor there.

Thanks for any advice.
I had a channel go out on my HPA2 some years ago, but since the reapair ( about 6 years )no problems since. I did hear that they have gotten more "reasonable" on the cost of repair. Before it was pretty much a grand to repair the amp, now it is something like 4-500 a channel if one goes out. I would highly recomend going for the higher powered HPA2, it will drive just about anything within reason.
I should have added, it has been over 11 years since I compared the HPA2 to an AMP2 at the shop, but from what I recall the HP series sounded more in control of the speakers the the BP series did. I think the speakers where Aerial 10t or Aerial 7's. It has been a ver long time ago so... keep that in mind.... LOL : )
I disagree about the reliability issues, I had and HPA-3 and HPA-2 for a long time and still have the HPA-2 for my rears. This thing has been on for almost ten years (with the exception of when the power hopes out!) and it works fine, sounds damn good to for the $$$$.

Proceed was a line designed to allow Mark Levinson's designers to try forays into the digital world (PCD-1) and the amps sound almost identical to the ML's for a fraction of the price.
Thanks gentlemen for the responses so far. I am well aware that Proceed is no longer manufactured or really supported (well) by Harmon. I've heard of issues with the AVP lcd displays and certain amps going into protective mode, but I believe that's mainly isolated to the Amp-5. For $500 I am willing to take a change on this older gear. It's not an insignificant amount of money for me, but it's also not too huge an investment.

I've heard great things about the HPA series. It might be that I end up going that route, but I do know it will set me back a little more than the Amp-2 or BPA-2.

I'd still like to hear about the sonic differences between the lines. I know the Amp line is the first and is rated at 150wpc. I know BPA came next at 125wpc and around the same time, if not at the same time, the HPA came out at 250wpc.
I had an Amp 2 for a while while then had the HPA's. They are pretty close sonically though I never had them both at the same time to do a direct A-B of them. Both are very smooth and natural sounding, with obviously much more power from the HPA series giving a little more bass control and headroom.