After updating my GT to v 2.0 I first encountered longish boot times - mine was up to 18 minutes, which was kinda boring, I'd say.

However, that was my own fault: I had just attached my GT to my laptop and simply replaced the internal data on the GT. You
shouldn't do that. Instead, use a V-Synth Librarian or a USB stick, load a project, save it as an internal and reboot your GT. Should be fine that way. My boot-up time with a modest project file is now 1 min 2 sec. In v 1.0 that was much, much longer.
Concerning the dual tone: I'm not too happy about that. I still encounter timing irregularities as GT's main processor is struggling with all the data it has to crunch. Also, it seems they've tried to avoid complicated factory patches - which is very well understood: it's not good rep to watch the screen go sludgy as you play just four notes.

What's better in v2, though, is arpeggiator timing. It's still not rigid and solid, but it's become usable. You know, if you need flamming, you play by hand... Also, two relatively complex tones turn the GT into a four-voice thingy, which is not something I'd call a GT. More like a 1.2d Combi Coupe.
Has anybody - by the way - ever asked why the loading times of Fantom family are so ridiculous?