Unimpressed!!
The 2 piece canister units look good. I'll bet they did a good job.
The single piece, self contained rental available in stores now, I've had bad experience with. I rented a Widetrack unit from Lowe's to clean a 3 story town house that I was renting. I only did one bedroom, I was very disappointed with results, usage and pretty much everything.
To start, it didn't say how much water it took and how much soap I should put in for that quantity.
It used tons of water but the carpet didn't look clean afterwards and didn't seem to pick up any more dirt or water on second stroke. Only when you push the button do you get agitation, but that means drenching the rug more. The unit is very bulky and when you wheel it forward you have to watch carefully dropping down the front. I like to shampoo all the way up to wall without marking the baseboards.
I took it back to Lowe's the next day very disappointed with the Rug Doctor rental. I then went to my local vacuum shop and rented a Rinse N Vac with straight suction extractor wand. Despite not having a vibrating brush like the Rug Doctor, the Rinse N Vac did a MUCH better job. The results in my bedroom where I had shampooed the previous day with Rug Doctor were dramatic. Needless to say to cleaned the rest of the 3 story town house with the Rinse N Vac. Did it all 1 day, 10 hours and the results were great. I prevacuumed everything with my Hoover PowerMax Deluxe S3607 canister vacuum cleaner!!