I'm currently deciding on which amp to purchase to pair up with my two GS112's. I want a great amp for rock that can get that grindy growly tone and also a more cleaner punch`y sound. After days of reading reviews and TB forums I've narrowed them to these two amps. I found a new SVT-4 for $995 and a near mint M-Pulse 600 for about $1000. I've tried the SVT-4 and liked it a lot, but I can't try the MESA. I've read some good comparisons between these two amps including BP reviews of both amps (the MESA gets the vote). I really need you to help me decide. I know I should hear stuff before buying; but I bought my Lakland Skyline and Aguilar GS112s' without doing so and I don't regret it for one sec. Which amp would you choose for $1000?? Is the MESA worth the risk or is the "sure thing" Ampeg the way too go. Thanks and sorry for the lenght of my post.