What's the main difference between carpet with attached backing and the one that uses a seperate pad?

Need to replace carpet in 2 rooms in order to sell the house. Is one type easier to work with, or noticebably better looking when installed? How about cost?

seperate backing looks better when finished, and can be stretched easier. Costs about 25% more

You get what you pay for. The foam backed carpets are typically used for glue down installations like on concrete, but can be installed in other rooms as well. Strip and pad installations are a better but more expensive route. If you are just going for a quick sell the foam backed is an OK choice as long as you choose a decent looking piece. The main difference is what you'll feel when you walk on it. The foam is not as dense as a good padding. I highly recommend nothing less than a 6lb pad. But if you want to increase the selling value, go with regular carpet. You'll have more choices in colors and textures, and you can still get some decent deals on remnant pieces and overstocks and inventory pieces also.

If you are just selling the house use the attached basking really all you have to do is lay it down with alittle carpet tape and you are done. The other is a ton more work, true in the long run it is way better but if you are just selling it get the attached pad. Then you don't have to get the tack strips and do all of the HARD work or pay some one to do all of the stretching. Attached you will easily be able to do yourself.