Genelex Gold Lion KT-88 reissued tubes

shuggie's are from upscale audio...the shuguang (sp?)kt88's. the gold lions i got from jim were well out of warranty & they are tubes so it can be expected occasionally. both mcshane & deal have always been top knotch

I'm considering replacing my Winged "C" 6550's in my MFA 200D monoblocks with the Gold Lion KT88 reissues. I need a total of 12 tubes so it is an expensive purchase.
I've been seeing a lot of reliability issues on this thread and was hoping to get more input from users of this tube.
I'm also curious about the sonic differences between the Winged "C" 6550 and GL KT88's. Another possibility would be the TUNGSOL 6550's.
The MFA 200D's are pretty powerful amps. 120 watts triode/220 ultra linear. The speakers I'm using are Harbeth M40.
I appreciate your input and hope to hear some helpful responses on the subject.

Frank, I haven't heard the Gold Lion re-issues, but I have and use both the SED 6550's and the Tungsol reissue 6550's. In my amps the 6550's are neutral, linear, rugged, and clear toned tube which are not overly extended. They don't favor any part of the frequency response. The Tungsols have more bass and are perhaps a bit soft in the highs. Mid-range is quite nice. A great tube if you are looking for more warmth from a cool amp or speakers. I haven't had a Tungsol fail yet either so from my POV they must be rugged.

My impression from what I have heard is that the GL's are SED's on steriods. If you decide to try them be sure to get them from someone who will thoroughly test and stand behind them like Jim Mcshane.

Thank you newbee for the response. I have Harbeth M40 speakers that are an inefficient load. The bass response is on the loose side so if the KT88's will have more control on the bottom end, I'd definitely like that. I also could use a little more top end as well so the Tungsol sounds like it may not work for me.

@ Flyfish, Newbee:

I am driving a paif or Martin logan Summit X's with two McIntosh 275's, and additional power would be welcome. Using a KT-120 sounds interesting, but here is my question:

If an amp is Class A, that means it's operating the tube in the middle between zil and maximum voltage (or current? IDK). If the upper boundary of voltage is raised due to a better tube, can a class A amp actually benefit from it? My logic says no, but I'm no expert.

Nils