Hi. I have CM5 bought it several years ago. I listened to it in 3 environment
1. At the shops listening room. The room was an ideal listening room with acoustic treatment. Room was not big about 5 * 8 meters guessing its been a while. The sound was really good enough bass to go around no need for subwoofer.
2. At my house. Big open space with low ceiling. Sound is good but need a subwoofer due to lack of bass. My friend let me borrow his old boston acoustic sub and together they sound fine. Been borrowing for 2 yrs already haha.
3. At audio show. It was setup w cm 9 in a small hotel room. The set up was horrible and the speakers sound like crap in that room.
Conclusion: i think the cm5 already sound pretty good for normal guy like me if setup properly. Room acoustic is also very important as well as speakers placement. So if you are on a budget i think cm5s are ok.
Downside: Cm5s are rear ported and i had to put them on speaker stands away from the rear wall which create clutter. They didnt sound too good when i put them on my tv shelf. So, if you wamt to put speakers closer to rear wall maaybe 502d is better and if price is no concern.
Fast forward to the present, im building a new house and will put meridian speakers into my home theater. I think they are great. you should check out meridian dsp3200 they are about the same size but look quite funky and sound great.