An age old question that I will attempt to answer with the facts and some years of experience.  Of course Leather is the romantic choice! It boasts of quality and luxury! However, the facts are that leather begins a slow drying and constricting process just after tanning. There is no absolute way to stop this, though you can slow it down a bit with the proper conditioners etc. The ‘outdoors’ unfortunately speeds up this process with moisture and sunlight. The constricting or shrinking is a very tangible attribute of leather. Over time, I have seen plastic motorcycle seat bases misshaped like a banana underneath a leather cover. I would venture to say  that leather may lose up to 50% of it’s original size.
A good synthetic that has the best sun and moisture inhibitors built into it will likely outlast leather by at least 50% of its life, if not 100%, and of course is a fraction of the cost. I base this on 23 years of experience, seeing hundreds of old seats in my shop, both leather and synthetic, gauging the age of the seat etc.
So, I simply give folks the facts. There is nothing sexier than a nicely appointed leather seat, however, you may also be amazed at the technology, selection, and ‘real like’ qualities of today’s synthetics. I stock a decent supply of both.    Happy Decisioning!