I think MCT-10 is an excellent cable tester for this price. Actually, for this price it's a must-have product. It will save you time, money and guess-work with those dreaded cables. If you're playing guitar and sing, cables of all sorts seem to be around you. And eventually they start to break up. Or down.
I bought it to take care of a box full of old bad cables I somehow collected in 20 years of playing in bands. I bought MCT-10, multimeter and a soldering kit to stop them the scrap cables from piling up any further.
I didn't experience and problems w/ battery compartment, seems to have "clicked" in firmly. Even tried to wiggle it about, after reading some reviews regarding it loosing contact. Didn't move a bit.
The only semi-issue for me is the position of the knob. If you look at the LEDs from the angle, while MCT-10 is placed on the working desk, the selector knob will obstruct your view of the lower middle LED. If you look at the LEDs from straight above, they're really bright! Nothing a normal functioning homo sapiens couldn't work around. Some moving of the head might help.
I'm glad Thomann/Millenium offers such products for a very affordable price. As I said: for this price MCT-10 is a must-have!
Very heavy, looks and feels like "army gear". If the insides were done properly (in China of course), it should last a long time.