I like the Mesa shock racks. There's no inner rack box or foam lining, less weight and better airflow. Still heavy though. And pricey.
For me, one of the primary advantages of a single rack system is that almost everything's already connected, minimizing both setup time and potential wiring errors.
I don’t use a huge rig:
Power conditioner
Rack tuner
Preamp
Amp
Wireless
...but there’s still lots of cables and way too many wrong holes to put ‘em in, especially under the pressure of “you guys go on in THREE MINUTES, or it’s coming out of your set!”
With a single rack, all I have to hook up is:
One power cable
Amp to speaker cab
House DI cable to preamp output
Footswitch (optional, for mute function)
...and I'm good to go. No hunting around for which gazouta goes inta which gozinta, in the dark, when we're already running late, throwing gear onstage with a 10-minute set change and no soundcheck...plus it leaves me a good 2-3 minutes to fix the f*cking guitard’s rig, or his wireless, or explain to the sound guy how the ****ing sampler works, or what-****ing-ever it is this time... ****!!!! $*%^#@&!!!!

:scowl:
Sorry, I’m back now.
Major drawback to a single rack: weight.
Not sure exactly what I’m gonna do when I start the next round of musical adventure. It needs to be a one-person rig, so it ain’t a-gonna be the “Hey! Help me move this!” 16-space Mesa rack anymore (the above gear plus a couple of rack drawers, great convenience but heavy as, um, a really heavy thing, I mean, yeah, it has wheels, but at some point you’ve still gotta LIFT the damn thing)...
I know what you’re thinking...power amp in its own rack is ONLY 2 more cables to hook up, what’s the big deal? I know, I know, I’m thinking about it...plus, as someone mentioned, I can see the advantage of being able to take all your “pre” stuff in its own rack...
I guess that’s about 4 cents’ worth...
