There's no install/tune a head at the gig with nesting kits. As per pic above, heads remain in tact and the shells split in half.
Heavy, yes, but there are several upsides.... the kit can be put in a case on wheels so it's only heavy at stairs/lifting into the car (as opposed to van), plus loading in/out the gig is easier (I also play bass, so I don't see a nesting kit as any heavier than a bass cab). Also, easier storage (I'll be living in an apartment next year). Other kits do this as well, but as Tree House offer many options, you can have the cymbals hanging off the bass drum, so less hardware.
There's bound to be some downsides compared to a normal kit (the floor toms are definitely shallower) but thought I'd give it a go. If I went for the smallest bop kit, now that would be v small and not very heavy, but I can see me getting carried away and buying the 20" with 3 toms!
I'm moving next year and most of my gigs will be in a city with small pub like venues (and I might have to get to some gigs by taxi), so compactness is key including getting rid of as much supporting hardware as possible to make for a small footprint. The 1 up, 2 down appeals as I can leave one FT behind if space is tight, and one FT can apparently be hung off the BD. So apart from being nesting, it'll be quite versatile and compact on stage.