Functionally they might do the same thing although admittedly I don't know much about independent. Maybe you can include a pic or link. You need to be able to see the display clearly so hopefully there is a wire from the encoder to the readout (as opposed to readout right by the scale kind of like a digital vernier). I personally don't use DRO bolt circle function much myself but that's only because I can spit those dimensions out in my drawing & usually its something oddball anyway. One thing I do a LOT is input an offset, so touch off an edge with a 0.200" diameter edgefinder, then input + or - 0.100" depending on if its on the left, right, top or bottom reference surface datum. This now 'zero's' the reference edge that you will be machining other features relative to. Similarly for less precise application you can kiss the edge with an end mill mounted, enter 0.000" then infeed the amount of material to be removed. Also as you are proceeding on a cut you will be measuring & comparing to the DRO so you need to be able to input an arbitrary number. Example DRO says 2.500 but you physically measure 2.502, you need to be able to input adjust to 2.502 & then carry on.
Most of the Chinese DRO boxes I see have tons of standard features. No issues that way. Its nice to be able to reverse the scale readout to set it up to your liking. There probably is an official machining standard or norm but for better or worse I chose X positive moving to the right Y positive moving away from operator. In quill feed/depth I have negative as depth. Another nice to have is adjusting display resolution so if you have crazy 6 digits after the decimal you can make it X.XXX on one axis or X.XXXX on another to suit your preference.
Another consideration is if you want to transport this DRO to another machine one day. If you need minimal features & will upgrade the machine to another that's one price point. If you spend some more & then sell the mill without DRO to use on another machine, thats another way to go. (Although the scales may not be usable based on length). Some things to noodle upon in that regard. Mostly I'd look for something that has been around & you can get replacement parts or at least compatibles.
