>Do two fonts of the same face, one a PostScript Type 1 font and one a
>TrueType font, have the same *exact* font metrics (character width,
>standard kerning, etc.) or is there a difference between them?

I'd be ready for differences. In addition to the other comments made here...

It would matter whether the two fonts had the same maker. I think
Bitstream and Monotype -- both of which released all or most of their
libraries in both formats for both platforms -- tried to keep the
metrics the same across the board.

Of course, there were also versions -- editions, so to speak -- of
some of Monotype's fonts. I had relatively early versions of Gill
Sans and Bembo (I think those are the fonts) that lacked kern pairs
altogether. This was remedied in a subsequent release. But if you
were comparing one of those early Type 1s with a newer TT that had
the kern pairs, you'd surely notice the difference.

Beyond that, the Monotype fonts that were produced in-house may
differ from the ones produced with the Adobe tools when Monotype
joined the consortium. This got very confusing. Most of the MT
library was redone, and the results licensed back to Monotype, so the
fonts would be identical to Adobe's. But some of the fonts Monotype
sold directly were their own, older versions.

I think similar issues could arise with Agfa (i.e., Compugraphic)
faces, though I can't think of an example.

Finally, you should expect differences in ITC faces from different
makers. ITC Garamond is offered in at least four different versions
(Lino/Adobe, Bitstream, URW, and ITC directly (and maybe E&F) -- not
sure which of these may be identical, if any.

It also matters what application (and in some cases which version of
an application) you're using.

Although I keep hearing that modern versions of MS-Word honor kern
pairs and always take advantage of fractional font widths for
printouts, I have yet to see a persuasive sample of a flush left
paragraph set with ostensibly identical specs (and with hyphenation
forbidden, as the methods for that vary in all these programs) in
Word and XPress or PageMaker. Given a 20- or 30-line sample, there
are usually fairly obvious variations in color as well as line breaks.

Assuming a normal word space setting (i.e., not XPress's wacky 110%),
PM and XPress should look the same if the fonts have the same
metrics, so that would be a good test for you.

Just a few possibilities that spring to mind...