Hag: "That's it! Since you won't get off my lawn, my husband Ambro will take care of you!"
First Knight: "Ambro's just a half-ogre. Prepare to eat my zweihander!"
Cleric: "Ambro looks more like a ogre!"
Second Knight: "What!?! He's a friggin' giant!!!"
I've collected both 25mm and 28mm miniatures since the mid-1990s. The vast majority are now 28mm, because they are more detailed, overall, than their 25mm counterparts. Yet I still like using my 25mm miniatures. But I'm a bit anal-retentive over their differences in height, and have been looking for ways to make my 25mm figures seem a bit taller. It doesn't help, however, that miniature companies have gradually increase the sizes of their miniatures over the decades, and some haven't.
You can find more about the differences between scale, and how companies come up with them, on The Miniatures Page.
From left to right: A Warrior priest of the Empire (GW--28mm), a knight templar (Reaper--28mm), a hag (25mm--MegaMinis), a hill troll/ogre (28mm Reaper), a knight (25mm MegaMinis), a monk (25mm--Ral Partha), and a cleric (25mm--Ral Partha). As you can see, the size differences can be noticeable.
Penny bases are the cheapest bases you can find (which is what the monk to the left is standing on). And were it the 1980s and 1990s, or if you don't use 28mm, they'd work out just fine.
My Solution: I've been mounting my 25mm miniatures on 20mm bases. That helps at least with the height difference, though no matter what, they will never look as bulky as a 28mm figure. You can see an unpainted version of the same cleric below.
Embellishing the bases helps, too.
My players over the years haven't made too many complaints about the height differences in miniatures. (Well, players with rogues and thieves for many years were stuck with the foppish guy in red and yellow stripes in the first picture before I got some more roguish figures).
Yet it amazes me how fantasy miniatures have gotten larger. You really notice the difference with larger-than-human sized miniatures. Trolls and ogres in 25mm are about the size as a regular 28mm hero today. The trolls below are from Grenadier.
Despite my preference for 28mm, I like 25mm, because they are quicker to paint (less detail + less space = less painting time). In between larger projects, or if I haven't painted in a while, I'll paint a couple 25mm miniatures to get warmed up.
Which do you prefer, 25mm or 28mm? Do you care about the difference between the two scales?