GU (or any gels) definitely take some getting used to, but then again eating anything while on the go takes some practice. I personally prefer GU brand and I like to squeeze them into a flask. I tend to only use gels for very long races (cycling that is, not much of a runner here...) where I'll need/want more than one anyway though. I also like that you can get unflavored GU. I've mixed my own with plain + soda flavorings (I've used cola and gingerale).

I've also found that I really like Powerbar's "Gel Blasts". They are like a shot block with a bit of gel in the center - but they are a bit more firm than most blocks. For me this is a plus as I've found stickier blocks to be hard to eat.