S10 vs S10+
The most noticeable difference between the two models is physical size, with the larger "plus" model sporting a 6.4-inch display compared to the standard S10's 6.1. The larger model is roughly the same size as the iPhone XS Max and other recent Android flagships–think the LG V40, OnePlus 6T, Xiaomi Mi Mix 3, etc. It's not a small phone per se, but thanks to the elimination of bezels in recent years, it's not uncomfortably large either. All of these recent 6.4-inch flagships should be completely useable by the average adult male. The S10, on the other hand, is small and easy to use with one hand. Both phones are surprisingly lightweight, at 157g (S10) and 175g (S10+).
The S10+ also has two front-facing cameras (the second being a depth sensor) compared to the standard phone's single selfie camera. This means the hole-punch cut-out is larger on the S10+, eating up more screen space.