The choice of Metric vs Imperial:
I was told in 1967 when I served my apprenticeship to start thinking and buying Metric tackle.
WRONG – when I semi retired 3 1/2 years ago we were still working in both metric and imperial alongside of each other. It's been like that all through my engineering life.
The choice really is down to what you intend to do. If you have any contact with USA items or old British stuff them imperial is advantageous. All else will be Metric. The Stuart beam engine I am almost at the end of is all imperial. I have no experience with any other kits available but others on here will advise.
At the moment I only have a metric Boxford which I hope to replace shortly. I personally also like the Warco lathes from all the imports, but I have only had British lathes before. My last lathe when I had the room was a Colchester Master. My choice will more than likely be another ex British machine like the Bantum 2000 or even something like the Boxford 330 toolroom lathe like what's running on EBay at the moment.
I served my time In the toolroom on lathes such as Hardinge HLV, the Monarch 10EE and DSG toolroom lathes.
If you buy a new machine make sure it's one that can cope with both metric and imperial threads if you intend doing any screwcutting.
DRO will sort anything else for you as it's just one button to switch between either. With your budget DRO for me is a MUST HAVE.