Pros - This is an excellent tool and does what it's supposed to. Also, if like me, you've bought pre-made pipes with the fittings already swaged into the ends you can disassemble the tool, then reassemble it on a fairly straight part of your preassembled pipe, straighten the rest of it and then disassemble the tool again to get it off.
Cons - it's quite expensive for what it is really, and it isn't adjustable/different wheels for different sized pipe aren't available which means I probably spent £60 on something that'll sit in my toolbox for ever more after only being used once. That said, as I have one of the larger sizes it'll probably do an ok job of straightening smaller pipe, which might be good enough for most things.
I've given it 4/5 because of the above, but if you just have one size of pipe to straighten or have enough (a whole car's braking system perhaps?) to justify the purchase price then you'll no doubt rate it 5/5.