I'm assuming that Seguin has trees roughly the same size range as the Boerne and Bandera area. A large trunk being no more than 2'. Normal trees having trunks around 1'. Most trees will be cedars with some scrub oaks scattered around a bit. With that in mind, nearly any available saw will be able to easily handle your trees.
I live between the Ozark and Ouachita mountains, my trees average around 2-3' trunks. I have several saws, my two oldest are a 40 yo McCulloch I got from my dad, and a 50 yo saw I can't remember the brand of, both still run fine, they're just a little brutal on the body. I have a few newer (less than 10 yo) Poulans that have been given to me, they were abused, but a little tuning and they're running fine. My 2 main saws are Stihls, a 250c with a 16" bar, which I use mostly for limbing and a 280 with a 20" bar that I use for bucking. I don't like the FarmBoss. I will be getting a larger Stihl for my larger trees.
Mt 250C is an easy start model with a quick adjust bar. There is no yanking on the start string, you just pull it out, at any speed you feel like, and a spring spins the engine.
All newer saws come standard with anti-kickback "safety" chains and bars. I hate them, regular chains cut much faster and are easier to sharpen.
I worked with the logging industry in WA state in the old growth groves for a while, they use Stihls with 36"+ bars. Those trees there are massive. My brothers and I got hold of a piece of one of the trunks, that one section was used for 4 houses and lasted 3 years.