You never told us what plane you intend to use these servos on. Since this is a beginners forum, we have to assume that you are not building a large scale gasser or large 3D machine, or a 2 meter pattern plane, which is pretty much where you would use digitals for. Most manufacturer's higher torque servos will work for larger models that beginners or those with a couple of years of experience would use.

So, a recommendation to switch to digital would be off the issue here. The OP requested to know the differences... that's quite different from a recommendation.

When I bought my DX7, it came with four DS821 servos that Spektrum describes as digital high torque servos. They are fine servos and cost about $30.00 US. But, they are not true digital high end high resolution servos that cost three or four times as much.

Consider what the need is before you select something that is way over what you need and will cost you a small fortune to use.

CGr.