Differences in tube sounds: 6550 / EL34

I would like opinions on amps that use these two types of tubes. In general, what charateristics do these tubes possess?
EL34 supposed to have more "lush" sound. 6550 are said to have better bass control. When i owned the tube gear I prefered the Ei Kt-90's over either Kt-88, 6550 or El34. Mostly out of reliability issues. Some amps built exlusively around El34 tubes could sound wonderful. Like the older CJ amps.
EL34's have a terrific midrange. They are very smooth and pleasing.
6550's have much greater dynamics and better control.
It's easy to get seduced by the EL34's, because they are so sweet sounding, but, overall, I prefer the 6550's for the dynamic range and overal tonal balance.
It depends on the application; In some applications 6550's are similar to SS amps-- Audio Research,for example.--AND of course 'what el34' matters,2.
I am considering two different integrated amps, one uses 6550, the other uses EL34. I am leaning toward the EL84 driven amp. What EL34 tubes do you suggest?
Dragan (Eldragon) is correct about the reliability of the Ei KT90. They are simply the best in that area. No other current production compares.

If you need the added gusto of the larger tubes, the JJ KT88 are my choice. 6550 tend to sound quite flat and uninteresting to me, as Averageguygeorge called it, "similar to SS amps". The KT88 adds a midbass fatness that I find intoxicating, along with sweet midrange and a nice treble.

Still, I think that overall, if you can get away with them from a power standpoint, the JJ E34L presents a midrange that is so good that you can forget about them not being so great in the lower frequencies.
My experience with the 6550 tube is in agreement with those who find it flat and uninteresting, sure does have nice bass control, however. Hard to beat the sweet midrange of the EL34 although bass is a bit soft. I prefer the SED version of the EL34, this is the original Svetlana EL34. The new Svetlana tube is essentially a Sovtech design.
I agree with Trelja on the tradeoff of a good EL-34 tube. I am using NOS Siemens EL-34's (12) in my Cary V12i. This amp also accepts other tubes including KT-88, KT-77, KT-66, or 6550. At the outset I was intent on tube rolling with others besides the EL-34. However, the Siemens NOS made me forget all about that. I'm sure the bass could be better, but its good enough for me and the mid-range and sweetness are exceptional.
I have just acquired an Audio Aero Capitole amp for demoing. It uses both EL34's and KT88's. I recently, today, changed out the KT88's for some 6550's. The 6550's do not have the base control of the KT88's but they do allow the sweetness of the EL34's to come through much more clearly, giving me the nearest to the C-J sound that I have lived with and loved for many years, only with much more articulation, detail, breadth and much else. Hope that helps.
I have to say that I very much like the EH 6550's that came in my Graaf GM5050. Good from top to bottom with excellent bass and a neutral midrange.