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?
gretsch6120
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?