I'm looking to add clipless pedals to my hybrid, but I'd like to keep the option of doing 10-15 mile rides in regular shoes. I'm leaning towards an SPD system with off-road shoes, so that I can walk in them.

I've seen suggestions to use Time ATAC pedals, instead of SPD. I rarely ride on anything other than pavement (maybe 30 feet on the dirt to avoid the pedestrians on the bike path, et cetera) and I keep my equipment pretty clean. I don't think the pedals getting mucked up will be much of an issue and I like the higher availability of SPD components.

The Crank Brothers Mallet has also been suggested, but the engagement area seems to be too high for comfortable use with regular shoes.

I also saw a suggestion for the Atomlab Quikstep, which seems like a good option except that it uses a proprietary cleat and costs $175.

So, I guess I'm looking mostly at Shimano's PD-M424/545/647 series, and maybe their 324. The 324 has one side for cleats and one side for regular shoes, but I've heard mediocre things about it.

So, on to the questions ... Anyone know how the 424 works with regular shoes? Are the 545 or 647 worth the extra cost? Should I give up the idea of using regular shoes?