I talked to a guy about it and he recommended cellulose. Its cheaper, does a better job, its flameproof, mold proof, insect proof and installation, although still messy, is a heck of a lot better than fiberglass. Plus you can blow in like 2x-3x thicker for the same price.
fiberglass cannot stop drafts either, while more densly packed cellulose stops drafts and seals the leaks. I got the machine for free for buying 10 packs at home cheapo, I think I ended up using like 25+ packs total? something like that, it was less than $300 and about 4-5 hours, but with many beer breaks.
Its a 2 person job. One to fill he hopper of the machine and the other in the attic blowing the shit. I also do not recommend stopping the machine mid load. Because the shit packs down in the tube while not mobile and can get clogged. It happened to me and it was a pain in the ass. So one its fired up make sure to empty the entire hopper before stopping. I found a reversed shop vac (blowing instead of sucking) inserted into one of the ends worked to free the clog.
Also, make sure you dont cover up your ridge vents. I was lucky and my house had 2x4 studs running around the house right before the ridge vents are stopping the shit from covering them, but your house might be different and you might need to add some styrofoam vents things (they look like U channels) running up your roof to stop the insulation and letting air run freely.