If you are planning this as a long-term meter (more than ten years for example), then it might be wise to find something which is a current model in order that re-calibration and spares will be available for a longer time. I've used my LunaSix-3 since about 1983 (when I bought it secondhand) and the last time it was serviced was about three or four(?) years ago - the following year it fell out of support with Gossen so any future needs will have to be met by third-party servicing or replacement with a current model. I think servicing and calibration of a Minolta meter may prove less simple than for a current Sekonic (although the 308 is relatively low-cost and it may be cheaper to replace than maintain it).

I also have a Sekonic L308S which I picked up new when I needed a flashmeter. It has no serious downsides that I can see (for my limited purposes) and it is conveniently smaller and lighter than the LunaSix-3. In reflected/incident use, my preference is usually for the LunaSix simply because I prefer the needle to digits and I occasionally use the Gossen spot-attachment for it too.