Suppose my mission is to carry no more than four people (that includes the pilot) at high speed for long range (more than 600nm).

It seems a Malibu is just as fast at half the operating cost. And easier to fly. And fairly comfortable.

Am I missing anything? Am I wrong?

-trying to pick my next fantasy plane.

The big question for many is how well to you fit in the pilots seat (and how easily can you get into it). For me it was to tight.

I have operated both. Both great planes.

This is kind of a Mooney 201 vs A36 issues.

The Malibu has no major downsides. It does everything you ask - carries 4 people fast, far and comfortable.

The 421 does the same, but a little bit more and always effortlessly. To do that you burn twice as much gas. Hangar, insurance and maintenance were about the same in my (limited - 2yr Malibu, 1 yr 421) experience.

The 421 has a small but real speed advantage over the stock 310hp Malibu, particularly in time to climb and particularly with equivalent cabin loads. I'd be more comfortable negotiating ice regularly in a 421. Malibu is FIKI, but the minimum climb speed in ice doesnt' give a great climb rate. (A 550 'bu or Mirage would probably be better)

Both great planes and my kids regularly suggest we should get one again. Overall advantage I'd say goes to the 421, but ... like a Mooney ... the Malibu is almost as good for less money.

I'm 6'3". I fit OK.

I've long said, the problem with the Malibu/Meridian cockpit is the size of the pilot's wallet. If it's too thick you won't fit!

I have piloted a 421 and right seated a Meridian. There is no comparison to cabin size and comfort. 421 is walk up wand sit down. Meridian is a wiggle in/contortion fest. Once in, you better have everything you need in arms distance, or repeat wiggle.

The passenger cabin on 421 is much larger with seats on pedestals instead of bolted to the floor. Was the load you plus 3 to equal 4? Or you plus 4 to equal 5? Big diference IMHO. Full fuel payload on a 421 will be 1,000 to 1,200 pounds. I don't know Malibu spec, but it will not be that much.

The best thing you can do is go look at one of each and then decide. Yes, OPEX on 421 will be higher.

I looked seriously at the Malibu before buying the 340. I just felt like it was an awful lot to ask from only 1 piston engine... (ie, pressure, turbo into FLs, de-ice, electrical, etc). i have nothing against SE, but lots of systems on a single engine.

It’s hard to find evidence of problems (other than cylinder//exhaust maintenance costs) of asking too much from a single engine. Plenty of Malibu accidents but overwhelmingly stupid pilot tricks.

I think one of the biggest knocks against the Malibu series is the wingspan, just in terms of hangar fit. A Malibu doesn't it in many/most t-hangars.

Otherwise, I think it would be my next step up from an A36. But then I'd have to have a small hamburger getter, thus requiring more hangar space.

The malibu is in my opinion the best airplane for the operating cost it gives you. You can go straight to FL250 (albeit slowly) and cruise around 205 knots all while burning a little less than 17 gallons an hour. If you get one with the 140 gallon tanks it has a stupid over 8 hour range. If I was going to go with a malibu I would make sure to get one with a 520. You have to run it LOP but honestly thats not a big deal. As other have said, it does have a really long wing span so hangar cost and availability could be a problem so I would check into that before purchase.

421 has higher wing loading by 10lbs (A little better in turbulence)i think, and lots of places for baggage- nacelles/ nose baggage is huge.

Kind of apples & oranges...

Major differences:
- interior size
- exterior size
- number of seats
- useful load
- potty
- baggage volume & capacity
- spinny things

I’ve been in a Malibu on the ground but never in the air. I’d guess sound volume in cruise is another big difference...?

If I went back to a single, hard to beat the capabilities of the Malibu/Mirage. I was at FL200 in the KA a couple weeks ago and a Malibu was was flying right with me at FL230 talking to center. Wish Beech made a pressurized single.
That being said, if you open the front cowling, they've stuffed ten pounds of stuff in six pound bag. Can be tight to work on up there, and as has been said, you're flying long cross-country flights in the flight levels with a plane that's got all the systems, but not near the capability of what many other planes with that mission have.
In my C90, I can be to FL200 in 12 minutes with an unrestricted climb at 140 IAS just for comparison purposes, and bleed air for boots, but much more expensive to fly and maintain.

Malibu and 421 both quiet. Pax don’t need headsets, 421 somewhat quieter but both very pleasant

Can't address the 421. I've now had my Malibu for about three weeks. It's a 1988 550 model. I have no issue getting into the cockpit (I'm 6 foot).

The plane is impressive. In the high teens I'm seeing 190kt on 14.5 LOP. Cabin is much bigger than my A36 and having pressurization is a game changer. The wing span is a problem as it doesn't fit in my old hanger and one has to be super careful taxing. My bird has a four blade prop making noise a non issue in the cabin.

Good luck with your search.

If a cruise ship is “a little better” than a ski boat in rough seas, then yes the 421 is a little better in turbulence.