In that case, may I suggest (if it’s even possible) having the current 1-5 rating system as well as a 1-5 difficulty rating that reviewers can also fill out?
That way you don’t have people knocking certain effects just because they were too difficult (they would just rate it a 5 difficulty and leave the regular rating blank), and it would also mean people could leave a 5 star rating and only a 1 difficulty which conveys that it’s an easy but very worthwhile project, or a 4 on difficulty and a 2 star rating, which suggests that it’s a tricky build that ultimately doesn’t quite live up to their expectations, etc, etc, etc...
Both would be optional (as in you can leave either field blank, or fill out both!) so people can have their review reflect their judgement as accurately as possible (maybe they bought the PCB for their buddy to build for them, so they can’t judge the difficulty; or they never could get it working, so they can’t judge the sound)