I've been using Pirelli's for several years now, My go to front tire is Scorpion PRO F.I.M, it's a soft / intermediate tire. Works really well on all of our local tracks. Very predicable cornering control and wears really good.
For the rear, I will swap between the older Scorpion 410,soft / sand / mud XTraX and MX32. The 410 is great mud and sand tire. I like the XtraX on tracks where it will be wet and deep in the mornings, but by the end of the day, will be packed and hard. This tire will handle various changing track conditions really well. MX32 is a great tire, I run this tire most of the year when the tracks will stay wet, loamy with no hard pack. I'm on a 250 2 stroke so tires seem to last a little longer than those on 450's. The Pirelli's seem to like tire pressure above or right at 12 psi.
I really can't comment of the new Dunlop range of tires, haven't used them in years, IMHO, I think they are over priced and based on my fellow racers who run them, they tend to replace then at a faster rate then me. I can understand why, being on 450's have a habit of chewing up tire quicker. So, I am a little bias towards the Pirelli brand.
I also have a local shop that stocks Pirelli's and offers them at a fair price.