Lots of fun and very flexible
Im not a musician or composer, but I am an electrical engineer, so I understand the theory of synths better than the average person even if I cant play one competently (Ive actually built a couple, way back when..). I was really impressed with this apps control over the waveforms and its depth of features. If you just want to make some very cool sounds, this app will do that right out of the starting gate. A person could spend hours tinkering with the waveform and envelope controls. A great value for about US$12.
Syscrusher1709 about NLogPoly Synth