Not true. Dassault is very much technically right. Extra wingspan is still more efficient than a winglet of the same length. There's a reason why long range Boeings don't have winglets. For the older Dassaults with the winglet retrofit kits, its a matter of loading. Those winglets are what the wing could structurally handle. Presumably a wing extension would have been more efficient but would have been too stressful on the wing. They are a compromise. Same thing with the 7X, actually. The winglets got added to the 7X design when Dassault changed their design goal from 5,700nm to 5,950nm, including an increase in MTOW, while they left their wing design mostly frozen. They could have made a more efficient plane if they went back and did a more substantial redesign to the wing to increase its length. Instead of spending the money to do that, they added winglets. Again, a compromise on total performance.

So maybe you could argue that winglets have proven to be a good structural / performance tradeoff, but even then you'd have to figure out why Boeing, a very aggressive winglet implementer, leaves them off of their long range 777s, 787s, and 747s.

Extra wingspan > winglets is still definitely the case

I don't know why QuietSpike is so defensive, but I do agree with him as far as saying that Dassault isn't necessarily safer than Gulfstream. Maybe has something to do with the fact that he is named after a Gulfstream research program .

The deal is that you're thinking, "oh the Dassault is safer because it can lose one engine and still have 67% of its power, and it can lose 2 engines and still have power." Well yeah and thats part of the safety tradeoff, but these turbofan engines are EXTREMELY reliable. Chance of failure of any one engine is something like 2% per 1000 flight hours. So most of the time you're going to have all your engines, and in that case the Gulfstream is going to have significantly better thrust and be able to power through dangerous situations better. Also, since the Gulfstream has much higher thrust to weight with all its engines, the Dassault's thrust to weight advantage with an engine out is relatively modest. Its not the difference between 50% and 67%. The Gulfstream has almost 20% more thrust to weight than the Dassault so with an engine out the comparison is something like 60% for the Gulfstream vs 67% for the Dassault, if that makes sense (basing all engine thrust at 120% for the gulfstream, 100% for the Dassault).

Either plane has all the redundancies that they need to be able to run all the systems with an engine out. In fact, before the 7X's improved systems, Gulfstreams were known for having better redundancies than Dassaults. Either plane be flown with all power out.

Also, engines aren't the only consideration for engine out performance. The wing is a huge factor. If the Dassault wing is slightly more optimized for high speed flight than the Gulfstream's (as it technically could be since it uses high lift devices more aggressively), then that could be the difference between the Dassault and Gulfstream's with engine out power. The Dassault would have a little more thrust, but the Gulfstream's wing would be a little more suitable to the lower speed flight that you'd be doing with an engine out. I'm not saying that this is definite, I'm just trying to convey the true safety difference between 2 engines and 3: not necessarily anything.

As far as efficiency, yes it is cheaper to run and uses less fuel. It also has about 10% less cabin volume than the G550 and can't fly quite as long, and is a newer design. The Dassault is more fuel efficient because it is so much lighter. BOW of 35,000 lbs vs 49,000 lb in the Gulfstream. Thats a huge difference, and yet the fuel savings isn't that huge. This is the way that Dassault gets better fuel efficiency while having 3 engines: their planes are MUCH lighter. 2 engines would have been more fuel efficient than 3. The dominant factor in choosing 3 engines is engine availability. There simply aren't modern and efficient engines available in the thrust class that would be needed to power the 7X. So Dassault figures that they can build the plane the 3 PW+C engines which are very popular and considered safe and efficient, and they'll still get better fuel economy than the competition by virtue of their plane being 30% lighter than the competition.

There are obviously a lot of tradeoffs 2 engines vs 3. However, overall, from an engineering standpoint, 2 engines is overall better. Like I said, its a matter of engine availability. Back in the day (the 1960s) all the purpose built business jets were small and relatively short range. The engines built for them offered maybe 3,000 or 4,000 lb of thrust. They were considered to be less technologically advanced and less efficient then airliner engines of the day, and also were relatively expensive to buy and service. So Gulfstream innovates by just saying, "we're going to build our plane around low end commercial airliner engines, which have much higher economies of scale and are better developed, and we're going to be able to give people much more airplane at a relatively good value". Then Dassault responds with the Falcon 50 by saying, "we're going to actually put some engineering into this problem and create an efficient S-Duct trijet so that we can give people the plane and range that they need at a much lower price than the Gulfstream".

And thats where they still are today. However, I predict that there will not be any more new Dassault trijet designs. They are over after the 7X. Every single engine make is currently working on engines in the current 10,000lb to 13,000lb gap where there are no good engines available. Without a gap between where efficient purposebuilt business jet engines end and where efficient commercial airliner engines begin, there's zero reason for trijets.