That Zoom looks cool, however from my experience, I tend to stay away from Zoom.
Keep in mind, I have not personally used the HD16CD.
As a background, I started with a 4-track cassette, moved to Cakewalk, upgraded to Cubase, got the original VS880 when it first came out, then went back to Cubase, which I still use. I also keep a Boss BR-900CD at my girlfriend's place.
IMHO, I prefer PC-based recording, mainly because of the user interface and ease of generating MIDI backing tracks. However, in my experience, PC-based recording is prone to complexities of getting everything working right.
Stand-alone systems are easier to use right out of the box and have lots of knobs for quick tweaking. However, editing and MIDI programming is a lot more tedious (although I just noticed you said the Zoom unit allows certain functions on the PC).
That being said, you tend to get what you pay for. I would personally prefer better preamps, better A/D converters, better on-board effects, etc. for better quality recordings over additional bells and whistles. Hard drive size usually isn't that big of a deal because you will fill it up and will need to back it up eventually.
I'd stick to Boss or Roland. Also, I have heard Yamaha makes good stuff, as noted by disassembled.
YMMV depending on your intended use.