The DS-1 is almost a fuzz pedal with certain settings, though as mentioned if you swap out one or two resistors for different values it can beef up the low end quite nicely.
If you're going to go with a Rat you should look for an old used one. The new ones are made in China and are really poor quality. Keeley won't even mod them anymore as a result. From his website:
"We are no longer selling new RAT II pedals because of the VERY Poor quality that we see them in. They are now made in China and the workmanship is the worst I've ever seen. We would have to redo/replace so many things that the cost would increase by at least $45."