I've tried all 3 of those tubes and prefer the JJ E34L. I find that it is the most balanced top to bottom - organic mids, not too bright, not too slow, and no lack of bass in my setup. Plus they are cheap to replace. There are proponents for each of those tubes, and ultimately you should hear them all to make up your own mind on what best matches your overall system.
If the total time is 100 hours on the tubes, that is relatively low and I would just keep them. I actually think tubes sound better once they have around that much time on them vs brand new. However, replacement may be a good idea if you do not know the history of the tubes.
The line stage tubes Jazz is referring to are the smaller 12AX7 tubes. If you feel the need to splurge on tubes, make it these ones and/or the phase inverter 6SN7 tubes. These are small signal tubes and as such will have a greater effect on the overall sound, more so than the output tubes IMO.
If the total time is 100 hours on the tubes, that is relatively low and I would just keep them. I actually think tubes sound better once they have around that much time on them vs brand new. However, replacement may be a good idea if you do not know the history of the tubes.
The line stage tubes Jazz is referring to are the smaller 12AX7 tubes. If you feel the need to splurge on tubes, make it these ones and/or the phase inverter 6SN7 tubes. These are small signal tubes and as such will have a greater effect on the overall sound, more so than the output tubes IMO.