Great summary on the jig saw options and blades above. Some additional thoughts based on my own experience and participation on the Festool owners group...
The trion really is a hidden gem and for the price, is really hard to beat. You can pick up lightly used models around $175 which is pretty compelling for a top end jig saw. One of the moderators on the Festool forum described the drivetrain as bulletproof. The carvex added an adjustable set of blade guides and simultaneously they introduced new blades as well. You need an Allen key to adjust the guides to the blades, starting by setting them tight, then backing off a hair. I have not had issues with my corded or cordless models, but I adjusted the guides as they indicated and only use the current crop of blades so I’m not dealing with variations in blade thickness. Still, there are a significant number of people that are frustrated by this saw. I’m not sure how much of that can be attributed to not setting the blade guides properly and how many were do to blades with different thicknesses. To Festool’s discredit, their written instructions ****, but they put out a 2 min video on setting blade guides that clears it up. I’m not sure about the blade change mechanism skewing the blade as described above. I haven’t seen that issue on two saws and don’t recall reading much about it on the Festool forums. But sometimes the damn saw won’t let go of the blade when I use the quick release, so it takes a little fiddling to change a hot blade. The ergonomics took a few steps back as well. The body of the barrel grip is fatter than the older trion and the switch is hard to reach from the position your hand guides the saw. It gets tricky when your second hand is supporting the work and you need to turn off the saw without damaging your work piece. Poor design that one might see past on a cheaper saw, but on an $$$ saw, hard to give them a pass. You also lose the ability to make beveled cuts with the standard base and the accessory base that allows this lacks adequate surface area on bevels. Poor design.
The Mafell is expensive, but when you consider they include almost everything Festool charges extra for on a carvex, it’s not that bad compared to the price of a carvex. And aside from a better blade guide system it’s ergonomics are really good (except the lack of a light). You’ve got a small circle cutting jig, accessory shim so you can run it on a track and still have support for the base hanging off the track. The base has a built in groove to ride on the track. Bosch track is the same track used by Mafell, so they are interchangeable. You can shift the base back if you need to get your cut closer to a vertical obstruction. Dust collection is very good...better than any jigsaw out there. The blower over the cut line is really handy (not unique to them, but partially makes up for the lack of a light). There are probably a few more I’m forgetting. The only con I can think of is it’s a tank (heavy). If you drop it...it will survive just fine, but your toes won’t! So don’t drop it!
The trion really is a hidden gem and for the price, is really hard to beat. You can pick up lightly used models around $175 which is pretty compelling for a top end jig saw. One of the moderators on the Festool forum described the drivetrain as bulletproof. The carvex added an adjustable set of blade guides and simultaneously they introduced new blades as well. You need an Allen key to adjust the guides to the blades, starting by setting them tight, then backing off a hair. I have not had issues with my corded or cordless models, but I adjusted the guides as they indicated and only use the current crop of blades so I’m not dealing with variations in blade thickness. Still, there are a significant number of people that are frustrated by this saw. I’m not sure how much of that can be attributed to not setting the blade guides properly and how many were do to blades with different thicknesses. To Festool’s discredit, their written instructions ****, but they put out a 2 min video on setting blade guides that clears it up. I’m not sure about the blade change mechanism skewing the blade as described above. I haven’t seen that issue on two saws and don’t recall reading much about it on the Festool forums. But sometimes the damn saw won’t let go of the blade when I use the quick release, so it takes a little fiddling to change a hot blade. The ergonomics took a few steps back as well. The body of the barrel grip is fatter than the older trion and the switch is hard to reach from the position your hand guides the saw. It gets tricky when your second hand is supporting the work and you need to turn off the saw without damaging your work piece. Poor design that one might see past on a cheaper saw, but on an $$$ saw, hard to give them a pass. You also lose the ability to make beveled cuts with the standard base and the accessory base that allows this lacks adequate surface area on bevels. Poor design.
The Mafell is expensive, but when you consider they include almost everything Festool charges extra for on a carvex, it’s not that bad compared to the price of a carvex. And aside from a better blade guide system it’s ergonomics are really good (except the lack of a light). You’ve got a small circle cutting jig, accessory shim so you can run it on a track and still have support for the base hanging off the track. The base has a built in groove to ride on the track. Bosch track is the same track used by Mafell, so they are interchangeable. You can shift the base back if you need to get your cut closer to a vertical obstruction. Dust collection is very good...better than any jigsaw out there. The blower over the cut line is really handy (not unique to them, but partially makes up for the lack of a light). There are probably a few more I’m forgetting. The only con I can think of is it’s a tank (heavy). If you drop it...it will survive just fine, but your toes won’t! So don’t drop it!