By genre, they really shouldn't be compared to each other but for the sake of argument, I'm going to have to say that HOTD is better for some very simple reasons.
I have the same problem with Bleach as I did with InuYasha, its gone on for way too long. Excessively so, & to the point where I really don't give a s**t about what happens according to story line any more because it all feels done before. I don't really enjoy the art styles of either anime in particular, but I can't help but love HOTD for the pure & simple fact that I will forever love zombie stories & the occasional ridiculously unnecessary panty shot. Fan service in anime is hilarious to me, so I gotta give it up to HOTD there. More than that, I find myself rooting for the characters in HOTD more than I do in Bleach because I feel like their survival plight is more desperate. I've always enjoyed animes where the people were human, that is to say, I've grown out of the phase where super human powers were a need for me to watch an anime.
Bleach comedy is dry - its all been done a million times before in animes just like it. HOTD isn't much better but I can't help but giggle just a little when it comes around. Just saying, but its really a matter of opinion. I put way too much thought into what I watch with anime, but that's just cause I'm a picky b*****d about things like that. If the anime goes on too long, I'm prone to lose interest in it & never go back - like I had with Bleach. Short sweet animes, with action, brief comedy, & the occasional flash of naughty bits are ones I can enjoy & watch again later if I ever get the urge to.
Better than both of these however, is Gungrave. I highly suggest at least watching the first half of it, the second half goes scifye & gets a little odd but its still good.