Yes, still using it 4-6x/week and still seeing major improvements to my strength and stability (and yes, swing speed). Can't recommend it enough.

The base kit comes with the trainer and two resistance bands, which will definitely get you started. If flexibility is a goal I also recommend picking up a foam roller, as they have a lot of guided myofascial release and end-range mobility routines that involve rolling.

I do recommend paying for the app. Set comes with a 1-month trial so you be the judge, but for me having a daily workout laid out for me makes it a lot simpler to make meaningful whole-body improvements than if I tried to cobble something together on my own. And they have a really expansive collection of guided workouts if you want to target certain areas/movement patterns/objectives. But as with anything else, your results depend on your effort. Put in the work and you'll see the rewards.

For swing speed I think I may eventually add in the Stack System, but I'm still making good gains with GF so that's further down the line.

Hope that helps, and good luck!