Funny how many people I know that own both a 365/512BB and a Pantera.
I have a '74 L and a '83 512BBi.
At first glance the two cars seem similar.
They should, they share the same mid engine design philosophies from the early seventies but one was designed as an entry level exotic and the other was a no expense spared design to be the top dawg in its day.
This accounts for the difference in fit, finish, performance and detail.
You asked about the following:
Drive ability?
Boxer has the Pantera on this one. The Ferrari has a much more refined ride as opposed to the raw ride of the Detomaso. Both are fun but your body will be much more relaxed at the end of a long drive in the BB.
Handling?
Again got to give it to the 512. I run both up in the Angeles Crest mountains here in Los Angeles and I can definitely push the Boxer father before my knuckles turn white.
Acceleration?
The Pantera sounds like it is accelerating like a bat out of hell but the Boxer is the faster car albiet with a much more reserved display.
Ergonomics?
Boxer wins hands down here,
Leather interior is top notch.
Seats are really comfortable and supportive.
Driving position is far superior, your feet are actually not offset!
And visibility to the rear is excellent for a mid engine car.
Baggage room?
Detomaso has a slight edge here but I've got the original leather 2 piece luggage set that came with my Ferrari. Both are good size bags that hold enough for two people on a weekend outing. One goes behind the seats and the other fits in the front boot. I must say there is no way I could carry a Beer Keg in the Boxer like I did in the Pantera though.
Servicing?
You've got a power plant in the Boxer that has rubber timing belts that have a finite life cycle and must be replaced. It involves an engine out service and this is your 8 year recurring expense. One other advantage for the Pantera is the long life cycle of the model and all the excellent after market vendors. This is lacking for the Ferrari and as a result a lot of the parts are now made out of unobtanium a really expensive metal!
Costs of ownership?
You have the belt service with the Ferrari and the cost of hard to get parts that create bigger service costs but when you factor in car values the Ferrari is actually cheaper to own. I have had my Pantera for 23 years and when I add the original purchase price and costs over those years I just about break even with its value today. The Boxer I purchased 4 years ago has more than doubled in value easily offsetting any service costs with money to spare.
If you are seriously seeking out a BB check out the Boxer section of Ferrarichat. You will find that the Boxer crowd is a little atypical for Ferrari owners. We are not the coveted car model as of yet and as a result you will find, what I believe, is a group of owners that are into the car and not the myth. Plenty of owners on the site posting detailed step by step articles on home engine rebuilds, new rubber and wheel swaps, electrical upgrades, air conditioning mods and even a couple hot Boxer resto mods! Much like what you see here. But with a lot more originality questions thrown in
If you are blessed with ability two own both I highly recommend it. You will have the biggest grin on your face no matter which car you leave the garage in!
I do need to leave you with my wife's statement on her first ride in the Boxer "Why the hell did you get this thing? It's just like the Pantera!"