I've got a Snap-on PH50E that I picked up brand-new at a yard sale about 15 or 16 years ago... The price-tag on it was hand-written, and said "100" rather sloppily... I handed the tool to the lady so she could write down the price in the notebook and she said "That'll be one dollar."
I ran all the way to the car.
Anyway, I haven't used it A TON, but I've certainly used it a good bit... It's ideal for breaking rivets on ball joints, removing old bushing shells from control arms, etc. etc. If you don't go balls-out wide open on the thing, and use controlled bursts, it's wonderful for separating sheet metal spot welds during floor pan and body panel remove-and-replace projects. They can definitely be a finesse tool, but are rarely used that way. If you do ANY restoration work, it's a must-have.
Mine has the spring retainer on it, and I've never seen the reason to go to the other solid-style chuck.
I've never broken the spring on mine either.
What's the advantage to the solid style chuck, or keeper?
-Brad