Safe, durable, easy to use, quality, no junk.
Primary use is S197 springs, I know, I know you don't have to but I need one in the 'ol tool box anyway so might as well pop now for any future use.
Nothing showed up local so online order is prolly the way to go. Got time, can wait. Don't really want to go loan-a-tool route.
I bought a set of used snap on spring compressors for very reasonable money on the Bay Of E.
I recently bought these and immediately put them to use multiple times:

they're quite stout and come in a molded case - best price I found was through Jegs. I'm pleased with my purchase.
I have the OTC clamshell its the only non-wall mount strut compressor I am comfortable with. http://www.amazon.com/gp/aw/d/B0002SRHU6
impulsive wrote:
I recently bought these and immediately put them to use multiple times:
they're quite stout and come in a molded case - best price I found was through Jegs. I'm pleased with my purchase.
I have those, but FYI they're too big to use with aftermarket Miata springs. The coils bind on the clamp hooks before you can compress them enough to get everything assembled.
impulsive wrote:
I recently bought these and immediately put them to use multiple times:
they're quite stout and come in a molded case - best price I found was through Jegs. I'm pleased with my purchase.
Just ordered that kit from Jeg's w/ free shipping. Looks like the same kit from Sears Craftsman just rebranded and more expensive. Sounds good. Thanks much.
In reply to impulsive:
Same thing I rented from AutoZone when I did mine. Worked well enough.
I've used my HF set several times with no ill effects.
I use a set of these:

link to amazon
It takes a bit more time to install on the spring than the ones with a less positive lock on the coils, but since there's no way for it to accidentally slip and release IMHO it's a safer choice. It fine works on stock Miata springs (I've done several with it, including my own when I first swapped over to 2.5" springs).
I picked up a set like logdog posted at NAPA for $22. They were a little bulky and had a hard time with front coils on a Tundra but I've used them on E30/E36/E46 mac struts a bunch with ok results. A billion times less E36 M3ty than the $11 HF single use ones.