The BM525S (S means updated model to meet current IEC requirements for CAT ratings) is in the same range as the BM829S. The biggest difference is that the BM525S has internal recording of up to 87000 readings and up to 20 times per second. IMHO, I actually think that the BM525s would serve most people much better than the BM869S. To make full use of the recording capability you need to buy the PC USB cable.