With over several hundred hours in light aircraft and several thousand hours in sailplanes I see them as very different activities. At the beginning there are some similarities in that one has to learn how to use the flying controls, take-off, fly around and land. But once one has progressed past the basics they diverge.
For many pilots gliding is all about soaring in an ever-changing atmosphere. Trying to fly further, faster, higher and for longer using only the energy freely available in the form of thermals, convergences, atmospheric waves and the wind blowing onto hills. Because it is all about reading the sky experience counts for a lot and one never stops learning. Some of the best soaring pilots are well past the first flush of youth because it is endlessly fascinating and never becomes routine. Not everybody wants to fly away from their home site and there are many pilots who enjoy aerobatics. Most gliders are semi-aerobatic allowing basic positive G manoeuvres, quite a few are fully aerobatic. Because gliding needs cooperation from other members to help you fly there is usually good club spirit where you get to know others. Most clubs have gliders for hire as well as those privately owned.
Learning to fly aeroplanes is equally interesting, but much more procedural. Once you have a licence and have taken your family and friends for a ride the question becomes what do I do with it now? Flying overseas is fun – but it takes you much more into paperwork and procedures for flight plans, customs declarations etc. To maintain interest one needs an aim. Some do more advanced training for instrument flying, or aerobatics. Others like to go touring. I’ve done those things but would have let my licence lapse if I did not use it for towing gliders. One of the more interesting aspects of that is retrieving gliders from some of the odd places they manage to land. Sometimes regular airfields, often places where light aircraft would not normally go – even farmer’s fields sometimes. Because one does not need assistance to get airborne power flying can be a more solitary activity – but it is less time consuming – and more predictable.
Neither activity is better than the other – they are simply very different. Sample both and try and see which best matches your longer term aims.