same for me: Broomstick Bass (with its drums) for testing, and EzBass for serious ( ) jobs are way better
Now coming to UJAM Sparkle, it can output good stuff, and I think this may improve using it without Scaler (i.e using bare hands on), but matching it to Scaler requires a too different, and less easy, setup compared to AAS Strum-GS 2
I also bought Sparkle on sale and I am not impressed. Their other VST, Silk, has a pleasant sound, but i found that all the UJAM guitar plugins are limited in what can be done, especially in the context of use with Scaler.