Anyone using fix-a-flat vs. spare?

[luvbowties]

Just wondered if anyone is using fix-a-flat kits ( like Wal-Mart's:>> http://www.walmart.com/ip/Slime-Road...ingMethod=p13n <<) in place of carrying around often hard-to-replace flats--esp. when on rear where wheels are difficult to remove due to width, lowering, etc. If so, which ones do you find reliable and easy/effective to use?

I notice so many new cars no longer furnish real spares, but use something similar to the above example, which injects a sealant and inflates in a claimed 7 seconds, or so. Maybe beats calling tow service and allows you to get home where you can carefully R&R, plus avoid dragging onto tow trucks which potentially could do damage to the underneath.

I also like the idea of not 'revealing' the spare on the bed, along with at least one jack--often takes 2 diff.-operating jacks to remove/replace the tire&wheel on the rear.
Thanks for input: I wanna hear positives before I invest in one.
Sam