McCormack REV B upgrades. Better than a new amp?

I have read the testimonials about the stellar performance of upgraded versions of McCormack amp,especially the "REV B" level. A "used good condition" McCormack DNA-1 bought for 750.00, with REV B. upgrades added later is approx 1600.00 with round trip shipping costs. Would it make more sense to find a another amp that is newer, though USED between $1200-1500?? Also, do the McCormack upgrades hold up over time??
I have updated a number of DNA-1's and it's a much improved amp afterwards. The whole mother board gets replaced and it's a good idea to do it. The new board is simplified. The original had some circuit board issues over time. I'm also a big fan of keeping the amp that you originally owned and sending it back. You never know if someone abused the updated amp you purchased, or overheated it.
I've had stock McCormack DNA amps, and ones modded by SMc Audio. As great as the stock amps are -- and they are plenty great -- the modded versions are right out of this world. Be advised, "Rev B" and the better "Rev A" were the terms that Steve McCormack's company used to use. He has since changed the nomenclature, using "Gold" and "platinum" and the like, I believe.
Also, you'll not find a better company to deal with. No affiliation -- just a very happy customer.
-- Howard
FWIW, I think Rev A, B refer to the DNA 0.5, 1, 2 series while Silver Gold Platinum refer to the newer DNA 125/250 series of amps that were built after CJ bought McCormack. Either way, Steve McC and Chris @ SMc Audio are a great resource. If I were still in solid state, I'd still have my SMc A+ amp.
Steve is a great guy. I'm happy to say I have known him for decades.
I think in the used market you're better off waiting for a Rev A unit or better. Given the cost of these units on the used market vs. buying one (new or used) and upgrading it makes buying an already upgraded amp a great bargain. I'd skip Rev B and get either a Rev A or Platinum given the discount on the used market and the significant upgrade in performance. Best of luck.
Agree w Soix that Rev A+/Platinum is the way to go.
Oh, forgot to answer your question about reliability. I'm the third owner of my 0.5 Rev. A and have had it for 14 years with fairly heavy use. The only thing I've had to do is replace a fuse, and as far as I can tell the amp sounds the same as it did the day I got it. Steve's also great about support if ever needed.
This is a little OT, as the only McCormack amp I ever had was a stock 0.5. Very nice sounding amp "as is" IMO.

Here's the thing: that DNA 0.5 I bought used arrived with a lot of damage, as the seller had used ridiculously poor packing. The whole case was "curved". I figured it was DOA, but hooked it up, & it not only worked, but sounded great (!). I sent it back, but I'm looking for another......
I had a DNA .5 delux and wish I still had it. I bet the Rev A and B are great sounding.
Thank you to all memebers who responded so far to this thread. There was a REV B DNA .05 for sale weeks ago, but I passed on it because I was making other upgrades to the system, and the seller would not budge on price It was modded in 2004.

However, it could be a long, long, wait for a REV A DNA.05 to surface on AG, and I am getting too old to play the kid looking in the candy shop window at Christmas. Also, it will probably be about $1800. which..seems like alot of money for a 100RMS amp

The other important issue is HOW MUCH BETTER can/or will REV A DNA-.05, or REV A DNA-1. sound. We all have a level of higher expectation, especially if he have owned more than one expensive SS amps, like a Pass, Boulder, Krell, BAT, Levinson. Personally, I have not. I had an Aragon 4004 MK II which in 1988 retailed for $1800, and I bought for $950 on a salesman's accomodation. It was a very good to almost great amp, though somewhat bright.

So what is the criterion of improvement, that gets one to say..." WOW, this is a spectacular sounding amp, better than any amp I ever owned or heard". The big gun brand names I mentioned above are at least 10 to 15 times more expensive than REV A+ Gold McCormack.

I currently have a pair of Red Dragon M-500 digital mono blocks(driving Acoustic Zen Adagios) which are remarkable for the money I paid. Yet, like other members, I am always curious about pushing the performance envelope a bulge or two more. No, the $27,000 Boulder or Levinson is not in my budget range or insanity border.

However, I like to hear what other members consider the basis of the WOW factor in amplifier performance. Thanks again, Jim
You should consider contacting Steve McCormack. I've found him to be most helpful, and I'm sure he or Chris would be upfront with you on the differences you can expect between the Rev. B and Rev. A, etc. When I spoke to Steve a looooong time ago he implied there is a big difference between B and A, but can't remember specifics (I think the power supply was significant) and what the final effect on sound was.

I seem to see 0.5 Rev. As come up from time to time, so the wait might not be as bad as you think if it's truly a big stepup on performance. I'll certainly keep my fingers crossed for ya.