I think Keeley mods are a matter of taste. I have friends who use Keeley modded pedals and swear by them. Me, personally, I had a Blues Driver and a Sparkle Drive modded at one point and ended up selling the modded versions and keeping the originals. I don't know if I was just used to the stock versions more or if I just didn't like the actual mods. The added low end muddied up the Blues Driver for my taste and kinda the same for the Sparkle Drive. It really depends on what you need out of the pedal, what amps you're using in conjunction, and personal taste. For some, I'm sure they're great.