RE: Which 4 stroke engine do you recommend?
As you have no preference for glow, gas or electric you will not likely be disapointed by
anything you choose.
Personaly, given the choice of electric or denistry I'd go for a root canal. Beyond that, i have owned around 400 glow engines, only 35 or so of which have been 4 stroke. Most have been OS or Saito with a few Magnums. None have been a real disapointment, though I lean toward OS and Saito with a slight edge going to Saito.
Much depends upon what you enjoy. I enjoy engines, be they in a car, motorcycle, or model airplane. I don't care much for electric razors, kitchen appliances or hair dryers.
This is, after all a hobby. Decide what you enjoy and go for it.
jess