I have the SL88 Grand, which is very similar to the Studio, but has a different Fatar keybed. That one is more piano-ish, but not very glissando-friendly - I regularly get blisters on my “sliding finger”. Not sure how it compares to the one in the Studio…
The mini-joysticks are a matter of taste - pretty short, so it is difficult to be precise when e.g. fading in strings via mod-wheel or doing exact pitch bends. I definitely prefer “classic” wheels. But of course, you get three x-y-controllers, so you can control more parameters - albeit within the limitations (different spring-loading: stick 1 re-centers horizontally and vertically, stick 2 only horizontally, stick 3 is fully free)
The display is nice and bright, but operations take a bit of getting used to: the labelling of the three buttons is about the most un-informative I’ve ever seen. Beside the buttons, you have the funky joystick-button-rotary control to do your editing. Every time I want to do some editing (admittedly rarely - I set up my one Cantabile profile and left it there…), I need to start experimenting how to operate the beast - which button does what, do I need to use the joystick or the rotary to do what I want, …
But overall, as a package, it is a good device - a minimalistic device focussed on being a keyboard (including aftertouch!) with a minimum of controllers thrown in. Pretty good as part of a two-keyboard-setup where you have all the faders, buttons, etc on the upper keyboard and just need a solid piano keybed for the lower level.
From what I see in some ratings, there seems to be a pattern of quality issues with the TP/100LR keyboard (rattling or squeaking keys) - I haven’t come across that with my TP40 Wood keyboard yet…
Cheers,
Torsten