I bought this device in order to improve articulation, presence and the "funkiness" of my basses. I only play at home and plug the bass directly into the interface and at times the sound is muffled or not clearly defined, and I've tried many basses, various pedals like expanders or compressors, and none of them really did the trick. So after hours and hours of research and watching videos and reviews etc I decided to experiment with this one.
There are two separate stages in this device: the pream and the cab sim. I've got one serious gripe with each of them, and then a third one that is about the device as a whole:
1. About the preamp, the mix knob ("dry"<->"wet"), when turned fully left, i.e. in the completely "dry" position should only reproduce the sound of the bass without any alteration. But this isn't so - you can clearly hear that the sound is affected by the circuitry: the accentuated mid-highs can be heard and different dynamics can be felt. So it's like if you plug the bass into the device you can't have totally clean sound. A big bummer for me. Thankfully I managed to improve the situation by this trick: I used the effects loop to invert the mixing potentiometer: I used a couple of patch cables to send the "send" of the parallel to the "receive" of the preamp and the "send" of the preamp to the "receive" of the parallel. This changed things for the better and although the preamp knobs need to be turned much higher to get the same volume of the preamped sound, it cleared-out the parallel signal and it's now much closer to the unaffected sound.
2. The cab sim is very impressive in its realism but the choices of cab and speaker sizes is limiting. I would like there to be something with tighter sound, like 2x12 or 1x12. All offerings leave this "big sound" kind of feeling that is not always good or wanted. I haven't solved this - I just don't use the cab sim very much.
3. If you have a sound with a mix of preamp and parallel sound there is no single knob that can adjust the volume of the mix. If you adjust the existing volume knob, it only increases the preamp side of the sound, not the overall mix, so if you want to do this you must increase the volume with the knob, and then alter the balance on the mix knob. Fiddly and doesn't guarantee that you'll have the exact same tone as before. So, in order to do this with a single knob and keep the exact same tone every time, you need a separate booster/volume adjuster pedal, especially if you use a passive bass and don't want to mess with its volume knob, which affects the tone.
As a final conclusion, after the trick with crossing/inverting the "sends" & "receives" on the effects loops, the device does what I want it to do and fulfilles its mission, as the sound is good - crunchy, articulate and "live". So the question is: is it worth the price. In all honesty, if you don't really need the cab sim, no. It's crazy expensive at 299. So, normally I would return it but I decided to keep it because it eventually does what I want it to do (albeit with the trickery described above) and I have grown tired of buying pedals in order to reach a particular type & quality of sound.