...

One thing to keep in mind is that Kodachrome has a reputation for better
archival stability than other slide films, most of which use the E-6
process. I don't know how much of a practical difference there is with
TODAY'S films and development, though; it's conceivable that the dyes and
processes for E-6 have improved to the point that they'd do as well as
modern Kodachrome. I know this wasn't one of the reasons you specified for
trying slide film (and I don't shoot enough of it to offer advice on what
to use), but as you mentioned the half-century-old slides, I thought I'd
mention it.

Personally I like Fuji Sensia, it has a much finer grain than the Kodak
equivalent (and I can buy it for around 33% less than the kodak film). Other
differences I've found are that the Fuji products tend to have a mild
blue/green colour cast, whereas the Kodak film has a mild red/orange cast. I
think Sensia might be designed for projection, because that blue/green cast
is not noticeable when projected through the warm light of a projector.
Kodak becomes very warm.
I have had a bit of trouble getting good scans of Fuji Sensia using a Fuji
Frontier scanner - the images tend to block up with blue, whereas Kodak
seems to scan much easier. I don't know if this is true of all scanners or
just the frontier.
As I said, I prefer Sensia, because it looks better projected than
Elitechrome, and I prefer projection.
IIRC, ED is 200 ISO and EB 100 ISO. There is also EBX which is 100 ISO with
higher colour saturation.

I don't know if modern E6 films will give the same archival properties as
Kodachrome. I know older E6 and E4 films weren't in the same class.

Well Thomas...I hate to bust your bubble but print film has a much
greater tonal range that Slide film. But your right about one thing.
Many slide films have a high color saturation for example Velvia,
Provia, and E100VS. Also much higher contrast which can be good or bad.
High contrast means you may not have much detail in the shadow areas. In
 spite of all that I shoot slides 10 to one over print film except for
weddings.
Smitty