Further observations after owning the phone for two weeks.
The phone has only skipped a beat once when for some reason the Productive Lockscreen crashed and I couldn't do anything except reboot.
Sense 5 has two things that make it flawed, in my opinion.
1. Blinkfeed - I've noticed that now I have emptied my Blinkfeed of feeds, HTC have 'helpfully' filled it with Tips and Tricks help posts instead. There is no getting away from it, it seems. I would rather have the option of removing Blinkfeed and adding it in when functionality inreases (my own feeds plus email accounts showing in there)
2. Only four rows of homescreen icons. Lots of space unused. Whilst I don't like cluttered screens, I do like to have more icons on my homescreen. Currently I have time and battery info on the top line of icons then three wildly spaced icon rows before the dock. I would prefer a fourth row in there a there is easily enough space.
I've switched back to Nova Prime for the moment and kept it as stock looking as I can (except for the two things above). When RSS feeds are implemented, as Earlymon says above, then I may switch back.
The battery life continues to be incredibly impressive for my usage. The average I am getting on one charge (according to GSAM, don't know how reliable it is) is 2 days 21 hours but I did get well over 3 and a half days on my last charge, which is unheard of for me. I consider myself a light to moderate user. For the most part I am a light user but probably once or twice a day I need the phone for a marathon SMS/email answering session and internet surf. Some days I have a heavier but more regular use. The nature of my work means that my phone habits change quite regularly and this phone battery more than keeps up with that schedule.