ARC Select Worth Price?

I had 2 iffy Sovtek 6550s in my ARC power amp. I replaced them with what I thought were well priced NOS Sovtek 6550 from Upscale. 

Now I am not an absolute expert on Sovtek tubes and their iterations throughout the eras but I do recognize obvious differences. In my case the Sovteks may or may not have been NOS but they certainly were NOT Soviet era tubes as my originals were. The newer tubes were noticeably lighter, thinner materials and apparently different metals at the base. 

I learned another lesson- relace ALL the tubes not just the weak ones. 

And another lesson: ARC matched tubes are in all respects superior to any I have encountered in the aftermarket. My matched set woke up my amp in a delightful way. More volume was the first surprise-- then the depth and detail presented in my favorite test music. It was a real joy to rediscover my music and my faithful old friend and room heater from ARC.

My local dealer let me have the ARC matched set at his cost. (He recently sold me some Maggie 3.7x so I had some good will leverage) 

My final conclusion: I got what I paid for- plus paid a stupid tax not going top shelf first. 

@hickamore you should watch Michael Fremer’s The Absolute Sound tour of ARC on YouTube. They do a lot of testing and burn-in of their selected tubes for ARC gear. Most look like new production EH brands, e.g., Tung Sol 6550s, etc.  ARC has built their own testing and burn-in jigs.  I suspect they’re voiced well for ARC gear.  I’ve always had good luck/good sound from EH Gold Lion power tubes. 

Upscale audio burns tubes in for 72 hrs then matches them.

AR needs tightly matched output tubes to perform at best.

Upscale would be fine

I have a AR 610T amp

AR factory wants 12K for a tube set. 48 tubes

Upscale sounds like a safe bet for my immediate needs. Thanks to all for the detail and reassurance.

I did get a response from Upscale. He said to buy ARC select only if you have Audio Research Equipment and that these tubes are selected to pass higher standards so to hold up better in ARC equipment. To that effect.