Originally Posted by delay
They are known to build up leg strengh far quicker than riding geared bikes.
^^^^ That OR ruining your knees.
Personally, I have found that it has been great for my road and 'cross training and has strengthened my knees. But you have to be cautious. I run a 48x16 on my fixed, and when I get on my geared road bike now, I tend to push really large gears, rather than spinning smaller gears (I like feeling like Jan Ulrich)...
Definitely put a brake on it. I know there are a bunch of fixed purists out there that might tell you otherwise, but IMO, brakeless is for the Velodrome only. It is not safe for you or those around you to run without a brake. Sorry to rant about this, but I was been badly injured several years ago by a supid ass driver and will not risk my life just to make a statement.
just my .02