Hi David (good name)
My preferences are Meister and Sino off ebay, you can get a 2 axis for around $420 posted (around 7 days)and 3 axis for around $550 posted (same 7 days).
I have bought 2 Meister's and a Sino years ago and am happy with them all. I have also never heard a bad word about either seller in all the years they have been selling. If you worried about sending your money, paypal looks after you and you can get a refund no problems at all, but you wont need it as these guys have a great reputation.
The Sino is a multi machine DRO, so you can set it in lathe mode on the mill to set angle up accurately using the taper function. Both readouts do all the things other do and to get any more gadgets (not needed)you will have to step up to the newer Newell's etc. Things like Bolt hole circle, ark machining, holes in a strait line, diagonal line, etc etc are all in them.
I have not heard a bad word said about the DRO Pro's either, but as Ed said they are more expensive for the same thing, that probably comes out of the same factory with a different name on them. The same goes for Grizzly, just more expensive.
If you where going to put it on a lathe I would have recommended a Sino as he will up grade to slim line scales for around $20 per axis and will also up grade to 0.001mm scales for another $20 per axis, DRO Pro's want $50 extra for 0.001mm scales, but on a mill 0.005mm will be fine.
Personally I would go for the 3 axis on a mill, why have a DRO on the table, but have to set the depth by dial, you would soon wish you had got the 3 axis.
Most people put a caliper style scale on the quill, but I bought an extra scale and swap it over depending on the job, but it will cost around $150 for the extra scale.
To this day I have never had a problem with any of my readouts or scales, the electronics are that advanced I doubt I ever will.
Dave