IR ThunderGun Impact Wrenches any opinions?

I've been working as a professional tech for 30 years now & have my own shop for the last 6 years & I beleive the IR 231 is the best 1/2" gun ever built! I also own an IR 244 which is rated higher but it has never out performed the 231! The 231 has broken things loose the 244 couldn't budge! I have 3 231s. 1 for work, 1 for home & 1 for a spare because I couldn't help myself & bought it used from a guy who needed cash & the price was right.