I would spy on your buddy's gear ratio as he rides (note what gear he tends to stay at most of the time, or at times you fall behind/get ahead), compare it to yours (accounting for his derailleur drag), and retool appropriate to what you want to accomplish.

I've heard this a fixie POV a few times. I ride ss freewheel, and I don't coast, unless I'm coming to an abrupt emergency stop or taking a really steep turn. Sure, there's a more complete workout of the leg with the fixie as there are forces to deal with in every point of your revolution uphill or downhill, but that has its disadvantages too. A lot of that "disadvantage" of a freewheel can be rectified with good-old-fashioned self discipline and technique, especially when we're talking about touring. Yes, riding a fixie may be part of the solution to that technique, however you'll have to reduce the gear inches on a fixie for the downhills (to sustain control), while the SS will give you a extra little advantage as you can spin a freewheel while coasting down, keeping your legs juiced, with no fear of spinning out. Because of this factor, you'll be able to run a higher gear ratio on the ss fw, which will help you out on the flats (it will work against you on acceleration, but once you're at speed, it'll be a higher speed at your maximum crank rpm). Also, if you're trying to compete with pops, the fact that you can't coast on a fixie is going to work against you on any considerable distance longer than a leisurely 1 hour spin. He won't waste energy stopping, or on declines. I would much rather ride a SS fw with a roadie than a fixie... unless it's on a track. A fixie is the wrong tool for the job.

At least in my meager experience.