I've been using them for years. So long, in fact, that my first heater was an actual immersion circulator from a science lab. They've come down in price from over 1000 to 100 or so and most of them are great now. annova is a good one I've given to friends as gifts. I use a couple of polyscience machines I've had for awhile and have no reason to replace them.
Any immersion circulator is going to be fine I'd bet. More important is the vacuum sealer.
If you decide you like the method, invest in a true chamber vac. They've come way down over the years, but they have more use imho than the cooker.
As for other cuts of meat, yes! I've done it all.
I rarely use it for steak unless I need to do a bunch of them for a party.
Short ribs are one of my favorites. Brisket is like cheating.
Vegetables can be fantastic and one of the best SV dishes you'll ever have is Alon Shaya's original roasted cauliflower from Domenica which he sous vide in a mont burre and then roasted in their million degree oven to finish.
Feel free to ask anything. I may have an answer.
Oh, and right this minute I have watermelon infused with moonshine and compressed in the fridge.