The regenerative braking makes it more efficient but also more expensive as you have to us AC motors but i imagine a lot of the road going electric cars are using them now...so using one of them is a good idea
But for a very simple set up a DC motor will be fine and cheaper with less wiring too... as always its horses for courses.. but cant wait to follow this project, good luck..
When i was planning mine the batteries became the straw that broke its back... i was only planning on running for about 10 mins all weekend so I could us only 6 batteries....cost over £4000..
