Older higher end or newer mid-fi...better bargain?

Old is best, my whole system bar Shanling CDT-100 is 2nd hand and I have never had reliability problems. Go for the large, reputable, established manufacturers. I have always had helpful fast response from Pass and Conrad Johnson, but I have heard good things about small new companies especially Rogue, Monarchy audio.
I 2nd the view about Pass labs power, I use the Aleph 3, clearly only suitable for sensitive speakers, mine are Living Voice Avatars. I also use a Conrad Johnson Prem 17, but some of the older premier models 10/14 are very cheap and excellent.
I enjoy buying used, there's more searching and interest, going to your local dealer is boring.

Go for the older cj stuff,outstanding,simply puts mid fi to shame,big time.

For even less money get some well modified Dynaco tube gear. It will show how little we have progressed in 40 years.