The original Old Glory figures are true 25mm so they are shorter than the new second edition 28mm figures. The new figures, of which I have more than 10,000, are 28mm from the bottom of their foot to eye level.
Hardly any miniature lines mix in the same unit. Perhaps Elite miniatures mix with Connoisseur, but the latter are skinny in comparison. So don't expect OG 2nd edition to mix with 1st edition as it is almost unknown for any figure lines to mix.
I happily mix units from different manufacturers on the table top but not in the same units. If you have identical basing that ties the armies together. Some people don't like to mix manufacturers, of course this is a matter of taste.
You can find some images of Old Glory 1st edition and second edition if you go back through my blog
link
One thing you may want to keep in mind is that OGs figures are really cheap in comparison to other manufacturers, especially if you have the 40% discount army card.
But the dollar is strong against the pound again and that may help you buy from a manufacturer in the UK.
I can let you see images of most of the 2nd edition figures (if not all) as I sell them ready painted for $2 USD each. So drop me a line if you need to see something.
Cheers
Neil
reinforcementsbypost.com