The Laverda solution
I don't know as much about the Mikuni RS (and its later variant the HS) carburetor as I would like to. But having worked with it a little, mostly in converting easy-to-find used four-carb sets for use on originally Del Orto equipped Laverda triples--a very popular application it seems and presumably owing to the original carbs' questionable reputation--I can claim physical familiarity, even if I lack experience tuning the RS. There are now kits available to rerack them for use on a handful of Japanese engines, but back then I fabricated all the bits--machined-from-raw stainless steel steadies, machined and silver-soldered fuel tees, intricately carved out and index-drilled throttle and choke shafts--to fit them to the Laverda. I understand the RS is also popular on big displacement vintage Hondas.

Adaptability
There are several aftermarket high performance carburetors out there. Only reluctantly do I speak of putting racing carburetors on a roadbike because the average rider experiencing average conditions is not going to benefit from a racing carburetor, though people keep trying. The Mikuni RS however may be at least one exception to this. Whatever the reason, this aftermarket carburetor is way more adaptable to various uses than a purely-racing oriented carburetor should be. And I mean adaptable in a way that spells less fiddling with alternate metering parts (jet needles and needle jets) than is the case with other non-original carbs. The Mikuni RS is surprisingly "at home" in a lot of applications. I greatly admire the carburetor for this reason.

Less sophisticated than Keihin
Early Mikuni carburetors, production or aftermarket, are crude. Paper float bowl gaskets, tapered float pivot pins, and all-metal float valve needles are just the beginning. Fortunately, the RS carb's crudeness, thanks to its performance, tunability and durability, translates to a very welcome simplicity. It just works. The only glitch is an accelerator pump that instead of diaphragm type has a metal piston that frequently sticks in its chamber. Early RS carbs also had plastic slides, which were known to crack. Later versions got more durable aluminum slides. Also, true flat slide carbs demand considerable throttle return spring force to counter the tendancy of the slides to stick (from the abundant surface friction), resulting in twist grip fatigue. These carbs also make a characteristic rattle sound at idle, which many find pleasantly exotic. And, the RS was never produced in a size smaller than 34mm, which fact limits how well they work on engines smaller than 1000cc. For all that, the RS is a desirable carburetor.

Look-alikes
When Suzuki introduced the first GSX-R750 in 1985, this non-US model was equipped with Mikuni carbs that looked very similar to the Mikuni RS. However, not a single part will interchange between the Mikuni RS and the Suzuki's RS-like Mikuni VM29SS. The two carbs' overall specifications are very different. The VM's throttle shaft is at the rear instead of at the front, the accelerator pump is in a different place also, and worst of all, being production carbs, the VM29SS' internal metering parts are Suzuki-specific and nothing like those in the RS. Thus the alternate jet needle and needle jet selection that Mikuni's non-proprietary carbs famously benefit from and which would allow the GSX-R carbs to easily be used on a GS1000 or KZ1000, is virtually out of reach. Many riders have acquired the VM29SS hoping to have essentially a "poor man's" RS, only to find they are similar to the RS only by being Mikuni and by have flat slides. They really aren't very tunable. Add to this the fact that nearly every 29mm VM29SS you'll encounter has been bored larger.

Part 24