I'd say unless you are intending on getting notecaddy to go along with HEM2, it probably isn't that beneficial to upgrade from HEM1. I mean, HEM2 has more stats, as well as other features that are nice to have, but it runs much worse (for me at least) than HEM1. It's slower, I feel like the layout is worse (liked the simplicity of HEM1), and I get problems with HEM2 either crashing or lagging very bad when I click the note icon the HUD (happens maybe 10% of the time, but is a real bitch when it does).

I'd say obviously try the trial first though to see how it runs on your computer. If it runs smoothly, then probably worth it. But if not, I don't see a huge benefit with it other than NoteCaddy.