OK I'll bite. If you buy the D8S I guarantee you will not finish 1 race. You MIGHT get through a qualifier, but I'm yet to see one make it to a main. The majority of people that buy a D8S are drivers with no experience and that car can't handle much abuse. If my friend that bought one would like to chime in about the D8S I'll leave that up to him. I'm sure he is reading this thread
The Losi RTR is a very nice car. It will perform well out of the box. The servos are not the best and will likely need replacing within a few months of purchasing the car. The plastic shock caps are a weak point and will need upgrade almost immediately. In the hands of a experienced driver that doesn't crash much you may be able to get away with them. The engine is good enough to compete with. If it can clear all the jumps at the Fear Farm it will likely perform well anywhere else. The engine on the D8S however does not perform nearly as well. I'm still using the same starter box with the same belt. A new engine with a lot of pinch will need to be warmed up before turning it over though. Once it is broken in that box works like a champ. I have had to change the wheel since buying it.
The RTR is a good route if you are not confident enough to build a car. Taking a car apart and putting it back together is easier than building a car for the 1st time. It is the main reason my 1st ride was a RTR. However... Within 2 months it was completely upgraded to a roller and then some. If you don't have the money to upgrade it immediately it will still be a good ride if you are a beginner
I know nothing about the JQ car so I really can't comment on it
Just to be fair and not seem biased cause I run a Losi. Here is a video of the JQ RTR car in action. It seems to perform extremely well. The engine sounds like it has some good power for a RTR engine. At $400 it seems like a pretty good deal. The one thing you will have to factor in is the cost to get it to a KIT car. You will be upgrading it.
Forgot to add the video.
http://www.youtube.com/watch?v=_M75avcP-Fg