No IMO.
I have a triumph and I keep going back and forth between it and my optimus.
My Triumph hits 2Ghz no problem and my optimus tops out at 800Mhz and they both have 512mb of ram. Something that isn't obvious is that the triumph has about an additional 100MB reserved for some good awful reason and that makes it tend to run out of memory after a few apps are launched. The most I ever usually have is a little over 200MB free and more realistically 140MB or so most the time. With my Optimus I usually have a max of 300MB free and a normal of around 260MB available.
I notice that it makes a bit of difference given different circumstances. Add the GPS issues that almost every triumph has and I'd say it's not even close to worth it unless the extra screen space is that important to you.
I can't begin to explain how annoying it is trying to get a GPS lock and then watching your data drop once you finally get one, but that's probably my biggest peve so far. It's a good phone, but not good enough to justify the upgrade I think.