The 210 is the better saw, in my view, for several reasons. It has a larger engine (35cc), and even with that it is on the small side. It has interchangable parts with the entire 1123 line (025,023,021,250,230,210). It also has the real saw bar mounts if you get the non-C model. However, I called mine the
wood massager when I had it. Not that great on power. I use picco low profile 3/8 on my 1123 saws, even on the 250 size. For me the picco pulls better than the .325 fat kerf.
The 180 is a good little saw, but the top is pretty flimsy. It also only comes in the C model now, and not with the regular type bar nuts. The 0.043 is a nice and narrow kerf, and the real secret to that saw's performance. I do not like the C model type auto-adjust plastic bar tensioners. They are weird and they can break. I prefer bar nuts. And beer nuts, for that matter
I do not know why they have same HP from that much of a difference in displacement. The 180 must rev higher, or have more torque. Gott'a be one or the other.