I prefer an analog but I use a digital. Analog give instant results so when you're exercising a bow you know you're not overshooting. I found it hard to find a reasonably priced analog with a big enough face so my old eyes can see it. The only disadvantage to an analog is that they depend on stretching a spring so the scale gets longer as the weight goes up. This gets in the way when you're trying to do fdc's or measuring string tension.
Digitals take second or two to display the weight so the numbers you see when exercising a bow are kind of meaningless. They use batteries although I've had mine for a year or more and I'm still on the original. Some digitals require two or three button pushes to get to what you want.
I like this one. It's Chinese(what isn't) about 4" across, goes to 300#, one button push. $35 Can I think.