I love the M8 aesthetics. I think it's the best looking smartphone out there. Actually, I've always liked HTC hardware. I've just had consistently bad experiences with the software side of their devices.
The first HTC device I owned had terrible graphics performance, despite coming with a decent GPU. It made no sense to me, until I discovered that HTC had refused to license the GPU driver from the SoC developer, so all graphics operations were rendered in software. HTC listed the SoC on their spec sheets, but nowhere did they mention that half of that SoC had been disabled, despite it being a rather expensive device. This was the first time I felt HTC cut too many software costs without being upfront about it. I had two more similar experiences, after which I decided HTC wouldn't be getting any more of my money.
I'd much prefer a device from Microsoft/Nokia, but right now I find their hardware choices very disappointing. If the W8 came out now I'd be very tempted.