The Slo V will cost less and comes ready to fly but the electronics are not suitable for any plane you may want in the future.
At least with the route you where headed at first you would have quality radio gear that can be transferred into a future model which will save you money down the road.
The GWS Slow Stick and the Parkzone Slo V are both pretty flimsy and neither one will last long enough to worry about upgrading the motor.