I have the Dowsar enclosure on my X. My wife still to this day calls it the best money we ever spent on the boat. Worth every penny. Still in great shape, but I keep my boat covered on the trailer so it doesn't get much weather.
We motor with the all the parts up ( you need to remove the connector to sail but actually can leave up the side curtains going up wind) and I've never had any problems with sight lines. You can see just as well with the wide Dowsar dodger as you can with any other dodger setup. Our dodger, connector and bimini are in place 99% of the time we are on the water, the connector can be flipped back on the bimini for sailing. No straps are needed to keep the dodger or the bimini standing and tight even if the connector is not in place. We've made a number of passages in very nasty weather all zipped up and cozy inside while the rain, spray, and wind tossed torrents of water on us. Our middle son sleeps in the cockpit every night, rain or shine.
The enclosure let's you use all 26' of the boat in all conditions. It's another separate room. With our aft cockpit lounge chairs we can relax in any weather while the kids can be doing their noisy thing below.
Lots of details here:
http://ddunn.org/ModsEnclosure.htm
I can't speak more highly of the product, but I bought mine back in 2003 when they cost less, we had a good exchange rate advantage, and they delivered the product in a reasonable time. I don't think they are using the same mfg now as they did back then.
I am also very well aquainted with the BlueWater product as I have a good friend who works for them. You are correct that there are no opening windows with screens on their product. To open a window you remove the panel. They do make a good product and there are a whole lot of X's and M's up here in the Pacific Northwest with them. BWY has sold over 1000 Macs so you see their enclosure a lot.
It is a well sewn product that seems to last very well from what I've observed on other boats that have had their enclosure longer than I have had my Dowsar. Even after years out in the weather all the time they hold up. They are build a bit lighter than the Dowsar with aluminum bows and plastic fittings. They are also not fully self supporting like the Dowsar design, you do have a few straps to deal with.
I didn't care for the BWY X version because it had the low under the boom bimini just like all the other choices available back then. Headroom was only 5'6" at the helm. The 6'4" headroom of the Dowsar plus all the other features led me to spend more for their product.
I think the BWY M version is better in some ways. The location of the M cockpit being further aft has allowed them to get more headroom under the bimini yet still stay under the boom. The enclosure also nicely wraps around and encloses the aft seats BWY sells. I'm not big on their use of a narrow dodger as it doesn't provide any protection for the cockpit seats, it only protects the companionway. With the full enclosure zipped up including the side curtains you do get all weather protection. They also look sharp in colors, at the Rendezvous this year there were great looking examples in a deep red and a forest green. I'd never go with black, it just gets too hot inside even in our meager NW sun.
, - needs to have a boat in Toronto area (we are located in Chicago) 
, + offers discount for multiple builds 
, phone price $1,300 Dodger, $1,400 Bimini & connection, $1,500 sides and rear curtain.
). I expect we will get the remaining components come spring. If I didn't already have those 2 main components, I would look at other options more thoroughly. I would concur with Duane's opinions of the BWY version, however the benefit of the narrow dodger vs a wider one is that you can go forward more safely when needed. It comes with threaded bolts to attach to the vessel, but I'm going to find some quick release pins of a matching diameter and replace the originals after the season; that will speed up the assembly time considerably. 
