Hey guys, for those of you who own one of these gizmos, have you found them to be useful enough to warrant a $25-$100 investment? I'm starting to move from extract to all-grain and I'm trying to figure out the essential hardware to amass and this one has got me stumped. I typically brew high-gravity beers and am pretty surgical in how I approach brewing, and having an accurate ABV is always something nice to brag about.