I've used these machines plenty of times. There great for blowing insulation into attics, but not dense packing walls or anywhere else.
It doesn't take more than a few seconds under pressure to clog the hose. I've learned this the hard way while trying pack insulation into my vaulted ceiling. I had a straight piece of 2" PVC pipe duct taped to the end of the hose. I had to carefully listen to the machine to make sure I didn't clog the hose. Even then I found myself banging the hose around quite a bit to keep the insulation flowing.
Trust me, you don't want the hose to clog. Not only do you spend a half hour cleaning it out, but it makes one heck of a mess. The first time the hose clogged it blew apart where the hoses were connected blowing cellulose all through the house. My wife was less than impressed
My advice is to let the experts with the powerful machines stick to dense packing. Use the free rental machines from Lowe's and The Home Depot for loose fill in attics. There's still plenty of insulating and air sealing for the rest of us.
Corey