I have used this system before and have also fixed leaks that happened due to the deterioration of the O ring, Im not convinced that its an awesome system.
Quick, Can be done on a wet or dry pipe ( soldering a pipe must be dry and not letting by )
No Flame so No risk of fire ( though I have yet in 10 years to cause a fire by soldier )
#1 COST of fittings. ( much more expensive than standard and not as easilly availablle )
#2 FAST, ( if the run is not thought out properly a inexperienced guy can quickly make a mess and have joints that are impossiblle to Crimp in their locations... see also #1 above, these fittings arnt cheap )
#3 Not as Tried and True as Soldiering
#4 Much heavyer than a torch to carry around, changing heads is a pain in the arse.
One experience that Pissed me off..
We had recieved one of the early models of these for our galvanized heating risers in a building and, being a commercial building ( condos ) we had not much room to rough in all of our pipes. We had several pipes in the given 2x6 wall, a domestic cold and hot riser, a Recirc, a vent stack, a supply heating riser, a return and another return ( system was a self balancing reverse return ) normally not a problem with sweat fittings but the heads for the Press fit gun ( press fit was for galvaized, Pro press was for the Copper ) needed a LOT of space for clearances between the pipes for sizes over 1 1/2 " if memory serves it required 3 1/2 clearance around the pipe to properly crimp it making it Extremely difficult to configure as we simply did not have the real estate. Also if the crimps wernt perfectlly alligned the machiene would crimp them at angles ( I HATE un-plumb Pipes ) I have also encountered a situation where the temporary power was not sufficiantlly powering the machiene and upon testing EVERy joint leaked making the "time saving" very costly ( personally I believe it was the heads being un maintained by the company that did that one though )
I should also note that it was in an area of great expansion and contraction that the o rings failed on the heating line... I have not seen a proper copper crimped line leak.... yet.
IMO.. Stick with soldier. this was maybe 6 years ago that I last used the Pro press system.