Yes, if there is one thing I hate with most multimeter designs, is a fixed back light timer. Brymens have the option to disable timeout for the meter, and to disable the beep, but the back light is as it is. More manufacturers need to provide a way to disable timeouts on the back light too.
The BM857S is a good buy but it is does not have temperature. If you need temperature and higher accuracy, than the BM869S is the better buy than the BM859S IMHO.