Well...I have had my blower option running for about a week now on my 7500 so I figured I would report back for any perspective buyers....
Keep in mind I owned a forced draft Wood Doctor WD14000 for almost 10 years and this 7500 with the fan is a totally different animal. That old WD would burn any type of wood, seasoned or not with 24 hr burn times not out of the question. Even with temps in the single digits during the day and 20 below at night, the WD only required to be filled once a day. Ok....enough about that defunct stove/company.
Sight unseen I took delivery of the 7500 in Sept. 2014 and was a little unprepared for it because all my wood was split in big chunks. The capacity of the 7500 is about 3/4 of the old WD. I learned quickly that the 7500 likes small, seasoned wood so I bought the fan option in order to burn some big, sometimes not 100% seasoned pieces.
My 7500 has 3' of chimney added to it. I run my temps 175-185.
First, Because of the door configurations on a Ridgewood, the fan does not fuel the fire directly but rather fuels the firebox. The concept still works but recovery isn't as fast.
Second, with seasoned wood, the recovery time is next to nothing. With mixed seasoned and green, recovery time is about half of the natural draft. Burning big split Ash rounds, recovery time is just a bit better than natural draft.....not much. I did not try green wood as I did not want to baby sit my stove with temps in the teens. All were tested with a nice bed of coals. Obviously the more moisture in your wood, the more you will burn trying to get up to temp.
Third, the fan set up makes it a pain in the ass to maintain the creosote build up (if you have any) on the draft door. I know a lot of guys (myself included) have burned up solenoids because of the door flap getting glued into place. Paper clips or not, you still have to maintain that draft door.
Last, a lot of guys ask if the fan was worth it. I paid almost $300 to get it to my house and I live in Michigan. Hook up was easy and the people at Ridgewood were great but I don't think I would buy it again. Instead I would try adding another section of chimney and/or stick to burning small, seasoned pieces of wood. Another option would be a completely new door set up, something that resembles Hawken, CB, WD....you get the picture.
Hope this helps