Over the years, I have bled way to many brakes on cars and motorcycles, most often by far using the standard two-person method, but I've also tried just about every 'time saving' device out there...
My thoughts:
speedbleeders. Gave up on them. Good idea, but after a while they start to leak at the threads, so you are always seeing bubbles in your clear line even if your lines/cylinders are clear. You can add sealant to stop the leaking, but that ends up offsetting any time savings I get from the bleeders.
Mityvac. Again, because you are using vacuum instead of pressure, they can give a false-positive for air in your lines when it really is just pulling air from the threads in the *******. I gave up on this too...
Syringe back-bleeding. This works great for motorcycles with small capacity slave and master cylinders and tiny reservoirs that are hard to get a good bleed on using the brake lever alone, can't see it working very well on a car.
Motive power bleeder. These things are really popular, and if I had a shop that did several brake bleeds a week, I might like it more, but my issues with it is 1) It's this big old garden sprayer sized tool I need to store that has one purpose only, 2) you need to dump the brake fluid into the Motive, and then deal with the unused/leftover (and slightly contaminated) brake fluid in the Motive when you are done, 3) cleaning the thing every time I use it or putting it away dirty, I like neither of these options.
What I've used most recently and is hands-down my favorite for bleeding automotive brakes is the
Power Probe Brake Bleeding Adapter. These are custom machined aluminum caps that go on your master cylinder and connect to your shop compressor at low pressure. It's kind of like having endless travel on your brake pedal and an assistant that always keeps the perfect pressure on the pedal. As it only uses the fluid in the master cylinder reservoir, you do have to top it off before beginning, and keep an eye on the level, and if you are doing a complete flush rather than a bleed, you'll need to pop the cap off and refill a few times. This extra hassle IMHO is more than offset by not having to clean up the leftover brake fluid from the Motive and store a garden sprayer sized device... Just throw the adapter in a small ziplock bag when you are done, no cleaning, super small to store, and it's ready for the next bleed.
They make a ton of different varieties for different cars, but the euro adapter (BA05) and the Ford adapter (BA03) fits every car I own and work on...
Whatever method you use, having a large magnetic bleed bottle makes the whole affair quicker and less messy...