i'm a huge fan of the v-max's. i do quite a bit of prairie doggin', and the v-max is what i use in my small rifles (223, 22-250).
i don't know what caliber you are shooting, but by art's reply, it is 223. in that case, look for something a little lighter than the 55's. have had best success in 223 w/ 40-45 grain bullets.
the moly debate is still going strong. if you start w/ a clean bore, and shoot only moly, you'll probably notice a decrease in cleaning frequency. velocity increases may/may not happen...it takes more powder to achieve the same velocity as an uncoated bullet. i used to shoot a lot of moly, but have since switched back to uncoated bullets. the problem i had w/ moly was that when it was time to get a thorough cleaning, the stuff was near impossible to get out of the barrel.
as far as effective range of the 223 on varmints, i think that is a function of the varmint you are shooting at. i've no experience w/ woodchucks/groundhogs. lots of experience w/ prairie dogs. for me, the 223 has been an effective killer w/ v-max and ballistic tips out to around 400 yards, +/-. beyond that, the 223 is traveling so slow that the bullets lose their explosiveness. actually, real impressive explosions cease around 280 yards +/-, but on pd's you can get reliable kills a little further.
short answer to your question...i'd pass on the coated bullets. they function fine, but moly is kind of a hassle.