Oooh chainsaws, love talking about toys....I mean necessary tools for having around the home.
The Stihl ms251 (All the ‘0 saws have been replaced with the ‘1 models if I remember correctly) is a good size homeowner saw. I think for what you need it would be fine. But I would only get it if you catch it at the $299 ($349 msrp). They run the $50 off sale a couple times a year from what I have seen. The 250/251 is a good balance of enough power without too much weight for home work to wear you out.
Growing up we always had Stihls. When I bought my first saw I bought a Husqvarna 435. The Huskys are good saws too, especially the true Huskys (i.e. the commercial saws). I upgraded from the 435 to a 465 which I got a great deal on. The 435/440/445 are nice and light but with a sharp chain will cut some serious $#%t. If you want to spend more for a new Husqvarna, I recommend getting the 450 Rancher bc that is the threshold where they go from mainly Poulan built parts to Husky parts in the 450 and bigger saws. But the 450 is a pretty good size saw so it will tire you out until you get use to it.
I am not super opposed to the battery saws either for small infrequent tasks. I have Milwaukee M18 tools so I would probably get their saw. The Stihl and Makita are nice as well, but Stihl is expensive of course.