How long do you spend fiddling around with configuring apps and themes etc? Probably about the same amount of time I'd expect
Probably more.........
This would be my first time rooting and flashing custom ROM's on a HTC device.
Pretty much everything that skyfall said
and mainly that you could encounter annoying niggles like battery drain, phone slowing down, restarts etc.
And what kona said, with Samsung/nexus devices it is incredibly easy and can be done in literally 5 minutes. With htc more steps are involved and it just seems more complex.
Also I hate doing backups/restores, when I tried that with my Samsung device I encountered more problems!
Therefore every time I start fresh, I would reinstall everything and set it back up from scratch (although saying that, if I flashed a custom ROM I would probably use stock apps instead due to themes)
I am looking through some guides now though.....However, as has been touched upon here, I would stick to sense based ROMs as they are likely to be more stable and have everything working and of course things like the camera being better. I don't know if it is really worth bothering with though as I am happy with the performance, battery life is decent (although improvements in this area are always welcome), audio is good, I like sense on the whole (just don't like some stuff like the notification bar and icons and white backgrounds) so essentially the main pros for me would be:
- themes, changing status bar icons etc.
- the HD youtube app
- adaway
- turning the screen of while playing a film on the TV with MHL adapter
- improvement in battery life and things like auto brightness