Steam condensers seem to be picking up "steam" (ha! pardon the pun). One thing that a lot of people don't seem to realize is how hot your brew room may get when using one. This would be a big concern for me and never seems to be mentioned.
Remember that kettles running hot create a lot of heat, even if there's no steam entering the room anywhere. The kettles are like giant radiators giving off heat.
One of the things I like about having a vent system in my basement brewery is that it I'm bringing in air from the outside to replace the steam I'm venting out. The air coming in will always be cooler than the air you're evacuating and this helps keep the room temp down. How much this helps of course depends on where you live. In my case it's cold 6+ months of the year and gets to -20C (-4F) in the winters here. This sort of cold weather is actually PERFECT for vent system brewing as the cold air coming in completely offsets the temperature of the kettles and my brew room is around 65F on the coldest winter days. Some people in colder climates setting up breweries inside the home have been concerned with the room getting too cold during the colder months of the year, but it's just not possible - brewing with a vent system in the frigid north is perfect and comfortable!
Now if I was to use a steam condenser, much of that heat would be in the room and would make the room uncomfortably all hot year round in addition to wasting a lot of water.
Keep this lack of heat removal in mind if considering a steam condenser. You could also use a vent but that seems to defeat the whole purpose.
This is all completely aside the fact that steam condenser systems do not remove as much DMS from the beer since you're boiling with the cover on and only boiling off a very little amount. Depending on who you believe, this can have flavour impacts (more obvious short term) as well as long term stability impacts (less immediately obvious).
Some argue that ventilation system are expensive, but factor in the cost of all that water (plus the environmental impact) of using a steam condenser when considering what you plan on doing. Even if a vent system is more expensive up front in terms of equipment, there's a point where over time the additional water costs will cross what you paid for the vent system and overtake it. Vent systems do use electricity (steam condensers do not) but most ventilation fans are relatively low current and will cost only a few pennies to run on a typical 60-90 min boil. The amount of water used during that time can be significant.
My 2 cents! Either way, good luck!
Kal