My first Alaska stoker stove had a 265 cfm distribution blower running wide open . Our basement was always at least 15 degrees warmer than the rest of the house. Alaska offered an optional 500 cfm distribution blower for this stove also.
My 140 has a 1650 cfm distribution blower with a variable speed and it's an option I really love.
I have it set to run when the plenum temp gets around 150 degrees and shut off when it cools down to about 90..
Without the speed control it would cool down really quick and kick on and off constantly.
I found my sweet spot at about half throttle and I no longer blow the wife's table lamps over in the living room.
And my basement is only a degree or two warmer than the rest of the house.
I'm thinking it depends on your duct arrangement and the size of your distribution fan weather the variable speed control fits your needs.
My 140 also has the 1650 cfm blower. My 140 seems to somehow restrict the flow of that big blower. The spot that I have the 140 is where my Harman SF3500 used to be. I put it there because there is a plenum into the main trunk there. The Harman has a smaller cfm blower, I think 1300 or 1400, but when that one kicked on it blow the curtins around upstairs, the 140 just bearly moves the curtins. I like my 140 setup a little better, the bedrooms in the back of the house stay a few degrees cooler the with the Harman.
I don't understand why this 1650 cfm blower moves less air, but it does and it is working out OK for me.
My fan switch is on the back of the plenum near the middle. My blower runs very long cycle times, no short cycling.
This pic is before I completed the tie in to the plenum. The fan switch goes in the hole just above where it is sitting in the pic.