These Mono cases are expensive, but they're about as protective and durable as any soft case can be. This is my second; I already have another standard Mono double electric case that I've used for years, but recently bought a new semi-hollow guitar and found it didn't fit, so bought this one for when I need to carry that along with another guitar.
Compared to the regular one, it's worth noting that this larger one sacrifices a little bit of space in the smaller side to make room for the larger guitar, which makes the rear compartment slightly less roomy than the two equal halves of the standard double bag, and means that your regular guitar has to be slipped into the case (rather than placed in with the case fully unzipped, as with both compartments in the regular double guitar case).
Something else to be aware of is that if your semi-hollow guitar has a long tail-piece (like a Casino or a Riviera, for example), cables stored in the front pocket will push down on the strings and put extra tension on the neck while it's being carried, which can obviously alter your neck relief slightly in transit, so if you're using it for that type of guitar, I'd recommend loosening the strings before carrying to avoid that.
My only general minor criticism of both cases is that while they only have one big pocket to store larger items (unless you pay extra for the optional add-on pouch), they're maybe a little over-replete with additional storage considerations which take space but (in my experience) end up not being used very much (for example, there are slots for pens in the top pocket, and a zippable pocket flap and velcro cable tie in the main cable pocket which I never find a lot of use for, but which does provide an extra thing to snag on items being stored there).
Otherwise, this is a well-made, sturdy case that does a great job of carrying two guitars fairly safely to practices/gigs/etc, and should be durable enough to last for years.
