difference between the UM2 and the UE10pro, worthwhile upgrading?

Heck yes! I've heard both but own neither, still i vote yes.

RX-7 fan, how did you hear the UE10 pro when I thought it was a custom mold?

It is not 3 times better.

I would say it is more like 20% ~ 25% better. Remember diminishing return starts to come into effect. Basically UE10 Pro fixes a lot of what UM2 not doing great, for example, the treble. After you heard UE10 Pro, you will feel your UM2 is definitely lacking in treble even if you have used treble boost on your iPod.

I say it is more detailed because you are not exeriencing any treble rolled off, and greater instrument separation. Also, the bass is more controlled, not as overwhelming as Westone UM2, so if you are a basshead, you might still prefer UM2. The bass quantiy is more out of Westone UM2, but quality wise, UE10 pro still wins.

I actually think UE10 Pro sounds closer to Shure e4c with an amp than Westone UM2 because of the pulled forward vocal.

Basically UE10 Pro is definitely worth that much money, but not something like 3 times better than Westone UM2.

I am listening to Tool straight out of the modded EMU1212 soundcard. The HD650 have more bass but god the bass is nothing less them amazing. The controlled attacking power is something else. The 1212m card being modded makes it cleaner in general and the bass is more pronouned. But boy they(UE10's) can take the power and then some. I having a hard time listening to 46 & 2 and working..

But no it isn't 3 times better. God the UM2 are nice headphones in themselves. I do think, which I stated before you need an amp to really bring them to life and they can't be feed alot of bass because leads to distortion. I find adding the amp controls the bass or cleans it up and adds a level of detail to the treble. Have I stated this before??? .. lol.

edit..

UE10 will sound better without an amp over the UM2s with an amp. Just a different level in IEM units. If aren't going to get an amp and you have the money UE10s. UM2 are truly missing something when they aren't amped. My option. If you can get an amp and listen the UM2s though it. Big difference. (Now imagine something better then that, you have UE10s.)

UM2-->amped UM2s (big difference)
Um2s(amped)--> UE10s unamped (small difference)
Um2s(amped)-->UE10s amped (not big, not small med. difference)

Again hard to put into words the differences but that is my best guess. Notice the biggest difference is with UM2 unamped and amped.

Oh I also wanted to note that, depends on your fit with Westone UM2. The increase in sound quality between a custom IEM like UE10 pro and Westone UM2 can also vary, but be assured, it is not 3 times more. For me, I am using tri-flange with my Westone UM2.