RE: Narrowing the Field to Three - Opinions?
I HATE shaft starts. It's just another battery to charge and another item to lug around. If you are not very good with pull starts they can be a pain, but I can start anythng with 2 pulls. Both systems require fitting of a less than ideally sealed backplate on the engine, so no advantage or disadvantage there. Eventually, you'll want a starter box, but in the meantime, my personal preference is pull start. It may be low tech, but it's simple and easy.
If you can afford the Losi RTR, then get it. There shouldn't be any discussion, it's hands down the best RTR on the market right now. People always complain about RTR engines and radios. The Losi comes with a good radio and a good engine. A rare thing. Don't think twice, if it's on the board, get the Losi (I'm not even a Losi fan, but the deal is too good on the RTR right now).