I think one question can point you in the right direction... What do you want to get out of the project?
Do you want to learn all the in's and out's of the woodworking, wiring, lighting, artwork, sound etc that is involved with a scratch build or do you just want a machine to play games in your basement as soon as possible? Projects take time because for most of us a lot of knowledge in a number of different areas. Personally, I love this aspect and expect my cab to take as long as my cab takes because when I am done I will know that I did it myself. BUT (big but), I also understand that not everyone has the time, tools or desire to complete the building of a complete cab and the only thing they want to do is play the games. You have the options of purchasing a fully built/fully functional cab all the way over to starting with a couple sheets of wood and a pencil. This includes every step in-between. Companies make all the aspects of this very easy if you choose to go that route. Cabs, control panels, artwork are all available already done for you but you are at BYOAC so you can see the way most of us are going to lean.

Good luck with your decision.