Some years ago we had a project which required the purchase of a large number of crimping hand tools mainly for red/blue/yellow crimps and the consistent production of such crimps in field conditions.
The significant cost of these tools in such quantity meant we looked at and tested several versions. Testing such tools was quite easy in that the test standard simply required a specified weight be supported on a crimp joint for a specified time (Pull out force) and that the voltage drop across the joint be below a specified value.
The only tool type which produced consistent results was the common ratchet crimp similar to the one Tony mentioned here
The pliers types were all very inconsistent and unreliable.
Of the ratchet tools we tried a few. At either end of the cost range were a CPC ratchet crimp tool at about £15 and a TE Connectivity tool at about £150. (They did another for about £1,500 but we gave that a miss).
The cheap CPC tool was as reliable and consistent as the TE Connectivity one. Of the 100 or so we eventually bought one or two required adjustment of the crimping pressure on receipt (using the small adjustment wheel on the tool). None failed and none drifted out of adjustment over about a years work and hundreds of joints.