This is a debate that will go on until... well, until geared bikes are no more. There are a vast amount of cyclists that will never try a ss because it is too hard, or they dont see the purpose, or my wittle hiney will hurt. Then there are the rest of that know what a ss will do for you.
If anything is worth doing, it should be hard, or at least challenging. If it were easy, why do it? Sure, you are going to work hard, but no other cycling discipline delivers a more complete body workout than does the wonderful world of monocogging. There is a hidden power in your lower body-not that hidden power-it is called your quads. You will get stronger wether you want to or not-and why wouldnt you. Riding a ss will reward you with powerful quads-not the girly man quads you now adorn. Riding a ss will also build upper body strength. There is no sitting and spinning girlfriend. You have two choices; stand and overcome the pain and the 200+ bpm heart rate or walk and overcome the pain and the 200+ bpm heart rate, but with the extra pinch of humiliation and ridicule from others. There is nothing, and I mean nothing more gratifying than passing a guy on ss whilst listening to the sounds of total exhaustion and just giving a grin and a quick "keep it up, you are doing great."
If you are a woman, dont think that I will take it easy on you. I know of a few that can rock it just as well as their male counterparts. My gorgeous friend Sandie is one of those. Very consistent and a real hard ass when it comes to riding. It takes dedication and mental toughness. She approaches her rides and races with the notion of catch me if you can attitude. I have had the pleasure of racing the same courses with her and she is just a great competitor. Sigh.
You dont need a lot of money to put together a ss either. As much as I hate to suggest it, but Bikesdirect has a ss for 400 clams. You aint getting a light bike, but a good starting point to get you going. You can turn any hardtail or unified rear triangle dualie into a ss for about 80-100 clams.
So put away the excuses and challenge yourself. The worst that could happen is that you never ride your geared bike again and selling it for a nicer ss. Win win situation.