Everything above is correct and I might add that aftermarket roller cams were not known for thier reliability on the street. Thier needle bearings relied on oil splash from the cam which is non-existant at idle, hence many guys found themselves with a motor full of needle bearings and a trashed cam. That's a very, very expensive repair, not to mention the tow bill. If the lifters were replaced on a regular basis, these problems could be minimized, but that's still an expensive and maintenance intensive proposition as BJR had previously mentioned.
As Rumblefish said, retrofit roller rockers are available now for the LA series engines that now have oil passages to supply pressurized oil to the roller bearings that should negate the extended idle reliability problems that had previously plagued this style of lifter. There is also a company that makes a roller lifter that rides on a ceramic bearing surface, negating the exploding roller bearing problems.
OK, that being said, the power gains that would be seen on a street Mopar with a hydraulic roller lifter is not as much as would be seen on a Chevy or Ford due to the Mopar's .904 lifter that allows it to run a cam with more lifter acceleration. In the hydraulic rollers lifters favor, you have a bit more power and a broader torque curve, the ability to swap cams without installing lifters, no oil additive worries, no cam break in and reduced friction.
Where a solid roller cam really shines is in a race or radical street/strip application where you can run insane valve spring pressures (read 6500+rpm style builds) that would tear up a flat lifter cam in no time flat.
So, now you have to decide what's important to you in a street engine. $1000 for cam, lifters and bronze oil pump/distributor gear for maybe 20 ft lbs of torque and 15 hp but no oil or cam break in worries, or less than $200 for really good performing street cam but with the usual oil and break in routine?