A coffee shop's transaction pattern is the opposite of a dining room's: many small tickets rather than few large ones, which flips which number in the pricing actually matters. A fixed per-transaction fee, the flat 10¢ or 15¢ component, hits a $6 coffee far harder proportionally than it hits a $60 dinner, and it is easy to miss in a sales pitch that leads with the percentage.
The maths is worth doing on your own numbers rather than trusting a headline rate: on $300,000 a year of card sales, the gap between a 2.5% and a 2.9% processing rate is $1,200, which on its own can be more than a year of subscription on several of the plans compared here. Square's free and Plus tiers are competitive on this without negotiation; Lightspeed and SpotOn's rates are more negotiable at real volume but need you to ask.
Modifier speed matters almost as much: a flat white with an oat swap and an extra shot needs to enter in one smooth flow, not three separate screens, because that friction repeats on every single order all day. TouchBistro and Clover both handle this well; Square's is fast too and has the advantage of running on hardware you likely already own.