I'd say it depends on how you see yourself needing the machine. Is it going to be used for vacuuming 90-95% of the time? If so, without a doubt, check out the PF51. It is totally off the RADAR for detailers, and I found it by chance. The specs were so impressive that I bought it. I love, love, love the machine. Very powerful with a great combo of water lift (suction power) and CFM (volume of air it pulls). They have an amazing return policy too if you buy it and are not blown away. It was on sale for $119 with $19 shipping to CONUS. Try to get them to honour that price if it's more now. They seemed pretty easy to work with. If you put in PF51 in the search, you'll see my comprehensive review of it.
If you are going to be using the machine to take out serious stains in mats or carpeting only, the Bissel Machine is OK. There are lots of shortfalls to it, but it is a cheap price. Folex and white terry towels will remove a ton of stains! That product is not to be underestimated.
After the vacuum, you should start thinking about a steamer....now you really up your game with one of those!!