Ravello system sounds pretty nice; Brian Myers also builds aluminum coupled bikes, steel coupled bikes, custom etc, prices seem reasonable. A lighter frame is helpful for travel bikes incl meeting airline weight limit with hard case.

About - RAVELLO: We're Travel Compatible

Folks focus on the assembly time but consider how couplers save time/money in other ways: no calling/hunting for bike boxes, no need to get a ride/taxi to & from airport/train station etc. With a cardboard bike box one can quickly assemble & ride away but airports (even in Europe) don't always have safe bike roads. With the S&S backpack case it's fairly easy to use public transport. Some "pros" even assemble their coupled bikes at the airport. Soft-side backpack case is light enough to lash to rear rack for the ride to hotel etc. Of course one needs a place to store the case but they are fairly small.

First-time packing is a hassle but just take detailed notes. S&S assembly improved my mechanical ability on components I wasn't previously familiar with. Disassembly/assembly can be done at home/hotel where one can relax more & not mind the time so much.

Some folks like coupled bikes just for ease of car transport: just unhook the couplers & remove wheels (<5 minutes) so bike fits easily into a small car.

I figure that if one is really interested in touring & is spending good money, why not get the coupler option? If one keeps bike as sole tourer for 10 or 20 years it's gonna pay off. Also a coupler retrofit is a nice excuse to get a custom powder coat. Production tourers are usually in mousy colors; Bilenky's powder-coating friends made my bike gorgeous & the finish is amazingly durable.