800.com? No, I guess. Manhattan? Yes, highly recommended. I have heard and would tend to agree that the tests are harder than the real thing, but not by a lot, so I think it is more motivating than anything. Also, something I bet most people don't use or know about are the assessment reports. You can view all of the questions of a certain question type, which is great for strengthening a weak area.
Furthermore, I believe you only need to buy one of the books for about $25 and you get all six tests. I bought all six books and don't feel bad about it even though RC was less than practical.
jfals
https://www.jaredmalan.comhttps://gmatclub.com/wiki/User:Jfals82