After owning all three adapter types (Tesla CHAdeMO, Setec CCS1, and Tesla CCS1) I thought I'd put a plug to compare and contrast all three adapters from my experiences so far.
Tesla CHAdeMO
Purchased at time of car delivery. Very big, bulky, heavy. Has a thick cable connecting two pieces together, and in use, feels like it can break off any second, which surprisingly, never happened, especially given that CHAdeMO connectors are also the largest and heaviest connectors of the three types. Max 50kw output, although a few people have claimed 75, possible, depending on the car. Pros: genuine Tesla product, doesn't rely on a battery (like Setec), CHAdeMO is usually available as the second handle to CCS1 charging machine. Doesn't need frequent firmware updates. Doesn't need Tesla charging ECU to work. Cons: Bulky, heavy, feels like it will break off, and discontinued. Used prices are through the roof. CHAdeMO is last place as far as availability compared to CCS1 & Tesla SC, as Electrify America, (A big DC charging company) is now committed to installing only CCS1.
Setec CCS1
Purchased a month after it was released, I think a year ago. Smaller than CHAdeMO adapter, weights a bit less, doesn't have the two pieces connected by a thick cable. It does have a questionable connection as it has a long neck and a heavy unit attached. So it's better than the above Tesla adapter, but not by a lot. Won't fit in glovebox or center console. Luckily, CCS1 connectors are lighter than CHAdeMO's so that helps. also 50kW max charging rate. Pros: Connects to CCS1, which, if you've ever visited a EA DC station, outnumbers CHAd by 7 to 1. Still available for purchase. Doesn't need a Tesla charging ECU to work. Cons: needs frequent firmware updates. It seems like every time the car updates, the Setec stops working, until the next Setec firmware is released. Also it uses a separate battery which needs to be kept charged. Fortunately, that can be done from the car itself or an attached micro-USB battery in emergencies.
Tesla CCS1
Purchased very recently. The smallest & lightest unit. Surprisingly heavy for its size. Only one that can be stored in the car's center console or glovebox. Fastest potential charging rate of the three, up to about 200kw, maybe even more, depending on circumstances, (charger, battery heating, outside temp, SOC, etc.) Pros: Relatively available, have to jump through a small hoop and a little wait to get one. At $318, a bargain compared to the other two. Genuine Tesla product. CCS1 availability is second to Supercharger. Cons: Not every car can use it, essentially a roll-of-the-dice, either the car can, or it can't. If your car can't, either wait (who-knows-when) for Tesla to introduce a program so it can, or buy one of the other two adapters (above). If your car can, this is the one adapter to buy, period. I'll even go further and say that if this adapter was released first, (provided all cars can use it) the other two would not exist at all.
For cars that don't have the ECU chip, it's a toss-up between the CHAdeMO and Setec CCS1. I don't like having to update firmware to keep the Setec current, knowing there's some times where no amount of firmware will work since the car updated too recently, and for the CHAdeMO I worry about pulling into an EA DC station and seeing a Nissan Leaf there (or other CHAdeMO car), and having to wait. If forced into a choice though, I'd begrudgingly pick CHAdeMO.
Hopefully I covered all of it, there may be more I'm sure.