ALT-1 How to Choose the right Motorcycle for you
I believe the comfort level of a bike should be one of the main criteria's for choosing a cycle in that if for any reason a particular feeling of discomfort arises it will be greatly exaggerated after an hour of riding or more.
The size of a bike is important as well because you should be able to have both feet firmly planted on the ground so as to be able to balance the bike when standing at a stop sign or traffic light. The engine size comes into play when you have mastered driving a bike for a while and you get use to the power it delivers. So choose a bike that not only "feels" comfortable when sitting on it, but will not leave you feeling you should have bought something with more power.
You can always adjust up to the power of the engine as you get more experienced, but if it's to slow for your particular taste, it may have been okay when getting use to driving a bike, but it will soon become apparent that one of the thrills in driving a bike is the sheer power and acceleration when you want it.
However, it's important to realize your own size compared to the bike in that you do not want a bike too big so that it controls you, but rather one that you can feel in control of.Upon first buying a bike, I asked if it could be delivered as I never rode before. The sales rep got a good laugh out of that request because almost everyone drives the bike off the lot.
Upon learning on side streets and parking lots, I soon got the confidence to enter the main streets, and once I've conquered all my fears and felt comfortable on the road, I soon began looking at bigger bikes with more power.
So as a suggestion, I would say it would be wise to rent a smaller bike before buying one so as to get use to how they handle and for improving you're coordination in handling the controls such as the brakes, clutch, and throttle. Once you feel comfortable, then it's a matter of choosing a bike that will fit you're particular size so that you will have maximum control and comfort.
All bikes pretty much offer the same experience in that the thrill of the open air and feeling at one with the road, but the big difference would be the kind of power that will provide the thrill of a lifetime. So by learning first, and then choosing the right size bike and power, you will not be disappointed.
Just like most people will ask a sales rep about which stereo sounds the best, it's not for the rep to decide, it's your own ears that will tell which is best, and that goes for choosing a bike. Comfort, power, ease of handling should all be up to you. After all it's you who has to be satisfied, not the sales rep.