Have any VAC owners tried any KT-88's

other than VAC's? If so can you share your experiences?
I tried original NOS Genelex Gold Monarch KT88, and Penta Labs KT88SC (Shuguang) in my VAC Phi 110/110, and I heard very little difference worth paying the extra $800 for the Genelex tubes.

In another VAC amp (MusicBloc 160), I tried Valve Art KT88, and thought they also sounded very good.

Frankly, in the VAC amps I have owned, I have not found rolling KT88 tubes to offer much improvement over the stock VAC tubes (which are hand picked Chinese Shuguang tubes as far as I know).
I've used Genalex Gold Lion Re-issues in my Avatar Super. I would agree with Tvad that there was not much difference from VAC's stock tubes, though the price is about the same. I found it made a bigger difference changing the tubes in the preamp section of this integrated amp.

Thanks for the input.
I believe the Shuguang tubes are made on the old Genelex manufacturing equipment. I have found them to be excellent sounding if they are selected and matched properly.
In my PA100 I prefer the "Winged C" tubes. When I had the Phi 110, I preferred the VAC tubes.
The "Winged C" is a 6550 which may not meet the KT88 requiremnets. Only the earliest 6550 could replace KT88. The VAC tubes were Chinese.
Winged C labeled KT88 on the tube and box. www.tubesandmore.com
I see, you can get just about any power tube with Winged "C" on it now.
YES- Svetlana(AKA Winged 'C'/SED St Petersburg)) has been making KT88s since(AT LEAST) 1999. I was using their EL34s in my ST-70, over 16 years ago.
In the ST-70s I always used Mullards. In VTL I had to use Mullards because nothing else sounded as good, besides they were still reasonably priced.
With Quicksilver I always let Mike Sanders sort the tubes because he knows best with his equipment.
After the Philips tubes ran out I started using the Svetlana St. Petersburg tubes in Audio Research equipment with 6550s.
Lately there seems to be some confusion regarding the Russian tubes.
There's no confusion. Some info: (http://www.stereophile.com/news/022304svetlana/#) It is important to know from whom you are puchasing tubes though, and whether those tubes are being honestly represented. There are some Russian tubes out there that are less than great. I've been dealing with Upscale Audio for years, and all of their Winged 'C's are fresh from the St Petersburg plant(no risk).