I've been using this work station for over 7 years ( I got two of them) and it just requires time and patience to make it sound properly, for sure you'll never make it sound like a TB303 but you can get really good new sounds, just think that every machine has a different purpose. The only but is the hiss.
This is an amazing groove box with 5 synthesizer tracks and a drum machine. The drums sound legit - it has really powerful kicks - and the synthesizer(s) are really good, also. The E-MX is super easy to use and still a lot of fun after years. The synths fall short in therms of polyphony and legit Acid, but this is acceptable. If you want to play polyphonic pads, you may add a different Synth, like the JP-8000, to it. If you want legit Acid, you need to add a TB-303 or clone. I replaced the E-MX's stock tubes to JJ Electronics. A huge difference! So, if you get an E-MX or an E-SX, take a tube upgrade in consideration.