I had both marks at the same time. I sold my lV combo for $1250 on eBay and bought a second lll blue stripe simul-class, EQ, reverb head for $500 that had languished for months on CL, plus sold the 416s that came with it for $100.
To each their own, but I find that the lead tone on the lll is the best Boogie tone for my style. I grew up Marshall and occasionally still use one, but I'm lost without my lll. It also has the most useable gain of any Mark, by that I mean it doesn't oversaturate or over compress the signal. The proper tube in V1 and V3 makes all the difference. They do not make for good bedroom volume practice. The master should be at 2 or higher, "loud enough to drowned out a chainsaw." Unfortunately I'm playing a lot of Rock and Blues these days, not my preferred metal where these amps really shine. I can get a great metal rhythm sound with a stomp box like a Boss Metal Zone or my favorite, an old Rocktron Rampage in channel 1. They're head turners with right tubes (that's right, it's the tubes, I can't stress that enough)! Getting a great clean and a great lead tone is possible if you compromise one a little. I don't need pristine clean anyway.