I received my brand spankin new 2006 Mesa MKIV medium head a few days ago. Surprisingly it only took about 30 days to arrive from Mesa after being special ordered. Thats fast service in my book! Its pretty rare to find one of these new in a store, so I pretty much had to buy blind in order to try. I played a MKIV a few years back, but I never really tried one again since. I immediately dialed in some great tones and was thoroughly impressed with the tone. I mainly bought this amp for the lead tone and Im not disappointed. This is a very tight/focused amp, especially with the eq engaged on the lead channel. Those who compare it to a VHT UL are not far off. It is not as quite as tight/focused as my old VHT UL but, its close. The MKIV has a bit more saturation and juiciness to its tone. The MKIV has a great cutting lead tone that holds together extremely well considering how much gain is on tap. Anyone worrying about whether these amps have enough gain can be assured they have gain to spare. Its definitely a high gain monster. However, it has a very different overall voicing from the Recto. The clean channel was also a nice surprise. It has a big, open clean tone with plenty of headroom and little to no breakup when driven hard. More than a "useable clean", it actually sounds great and has plenty of volume to spare. I haven't spend much time with R2 yet, but it seems to be a pretty straightforward semi-dirty rhythm tone (blues to classic rock). The main selling point of this amp IMHO is the lead channel with EQ engaged (in the classic scooped V pattern). The lead channel does not disappoint and easily provides the familiar Metallica tones of old (AJFA, Black album, etc.). Whitesnake & Petrucci fans will also be in for a treat as well. Solos are a breeze, and the amp easily keeps up with the fastest runs. Also this amp is pretty loud when run flat out on full power; its one loud mofo. When you cut the power in Tweed mode and switch to triode power, the volume is more manageable and the sound is definitely sweeter. I know many people claim this is a tweakers amp or you need to be a rocket scientist to use one, but I simply have not found this to be the case. I did some homework prior to getting mine, and with all the settings you can find online, there really arent as tough to dial in as you might think. Overall Im really happy I decided to give the MKIV a shot. If anyone has any tips, tricks, or settings feel free to share!