I own an 8" LX50 which is essentially the same scope as the LX90 except for the electronics basically.
Unfortunatley, because of a bad back all too often and almost no time to observe, I seldom use it because it is still a bit of a pain to setup just to view for a few minutes.
But, because I now also have a smaller 120mm wide field refractor on a lightweight mount, I am out every night it is clear, even if it's just for a few minutes.
The best scope is one you will use the most. There is nothing more true than that. Still, the LX90 has almost double the aperture and four times the light grasp of the ETX125. There are times when I'm out with my 120mm refractor and I can't make something out and I wish I had the time or the inclination to drag out my LX50. It's nice knowing I have the 8" LX50 when I do want to use it.
I do have my LX50 with it's mount and tripod on wheels (see the other thread about "Making larger SCTs more portable" and my reply... http://www.astromart.com/messages.asp?message_id=36040&page=3).
It has made my 8" LX50 far easier to take out. But I only roll it out on my driveway and right now the winter constellations I view are on the other side of my house when I observe, so I don't use it as much in the winter.
If it were only a matter of aperture, I'd say go with the LX90. You can make it easier to setup. Still, if you plan on going anywhere with it or want a more "grab'n'go" type of scope that you may use more often, then the ETX125 is the way to go.
Have I "muddied" up your decision enough for you?