I've been considering a Lonestar also. Right now I have Mark III that I love very much, just looking for something to compliment it. Keep us posted on how you like it.
These are totally different amps. The V may give you cleans as good as the Lonestar but the Lonestar has a lead tone in it that the Mark V will never give you. The V can get heavier and probably has uber-gain. Depends on what you want. I never played a V but prefer the Lonestar to the Mark IV.
+1 I heard a LS special a few weeks ago that blew my socks off, but its not a metal machine. class A with the power dropped down, the lead tone was fantastic. I guess it comes down to what you want out of it. {'m sure the MK5 has more tones, but man that Lonestar SP was sweeeet