I started thinking, why $20. All I can come up with is $20 bills, $20 chips, it helps with pay-outs.
It doesn't really help with cash-outs. People cash out with whatever they have, and it's never solely the big chip. It'll be a bunch of different denoms, and they'll add up to some number that has nothing to do with either the 20/25 denom.
It can help with buy-ins,
if you get a lot of $20 rebuys or top-offs
and you don't have enough $5 chips. In my games, a $40 rebuy will get 8 $5 chips, or if I'm getting low on them, it will get a $20 and 4 x $5s, or it will get a $25 and 3 x $5s, depending on the set.
If I were making a micro set with limited $5 chips, I might use $20 chips to ensure that $20 bills are easy to buy in when the $5s run out, but with ample chips, it's simply not a reason. If your crew somehow tends to be topping off with single $20 bills over and over in a game that actually plays big enough to run out of $5 chips, maybe the $20 chip makes a lot of sense, but that's not my world - in my 25c games, people are buying in with $40-$100, not single $20 bills. And when I have a micro-micro game where people are buying in with $20 at a time, running out of $5 chips is not an issue; I needed them for my normal 25c game!
In the end, the $20 bill = $20 chip argument just never really makes sense for cash-outs or buy-ins, to me... but I like a $20 chip just fine.
If chips are really unlimited, I prefer the $25 for cash. I like that a stack of $25 is a rack of $5, and a stack of $5 is a rack of $1. (Quarters and hundos don't work into this.) And I cut my teeth on green $25s as a dealer... but sometimes I like the color on the $20 better than the $25. That's true on the Boardwalks - love the yellow $20; not so keen on the green used for the $25.
But if the chipset will be super-limited, I'll want $25 chips. More bank per chip is more efficient in an absolute sense. When I run out of $5 chips (which is inevitable; super-limited), if someone tops off with a $20 bill I just change a $25 chip at the table for five $5 chips, give four to the player, and put one in the rack as I deposit the bill. Easy-peasy.
So, unlimited redbirds? I prefer $25. Super-limited redbirds? I prefer $25. In between, I'm cool with either.
For tourneys, I like T25, because counting stacks worth T500 seems somehow easier than T400.
Then again, if you're using a T2000 instead of a T1000, there's something to be said for T20/T100/T500/T2000... a rack of T20 is a single T2000. And starting blinds of 20/40 allow you to have a slightly lower starting blind and perhaps a smoother progression, though some people might get tilted by unfamiliar blind levels.
If you're creating one theme for cash and tourney, there's a lot to be said for $20 in cash and T25 in tourney - most low-limit games can use the $20 as the top end and skip the hundo entirely, and you avoid using the cheapest, most abundant tourney chip as the rarest, most valuable cash chip (risk!) A lot of custom sets take that tack. I don't recall seeing a tourney set made with a T20 low end.
