Strengths: Super clean signal. Good low-pass features. Compact size. Does not get hot.
Weaknesses: Only has a low-pass filter. A high-pass option would make it more versatile.
I gave it four stars (rather than 5)because of the retail price. I haven''t used any low-budget/low-power amps to compare the quality with.
Summary: I purchased this unit on closeout because it was cheap and I needed an amp for my rear speakers. I have since ditched the rear speakers and have the 3520 powering a single ported 12" sub (JBL LC-S1250W). This is an ideal application for this amp. The amp does 90 watts at 4 ohms bridged at 13.8 volts. This sub is no SPL monster but is very efficient in the ported box and the 3520 powers it nicely. I''m using all of the features that came with the amp to run the sub... the variable low-pass filter set at about 90 Hz and the 45Hz bass boost. The amp will easily push the sub to the point where I cannot use more bass because of the rattling sheet metal in the car. Again, this amp/sub combo is for daily driving, SQ bass-fill and not for competition. It will easily move the rear-view mirror with the right music and gives the impression of much more hardware stashed in the trunk.