Welcome to the forum Jimmy! 
I don't know if I would go so far as to say the X series is commercial grade. I have an LT150 which I suppose one could say is the predecessor to the X series. My uncle has and LA model he bought last year for about half an acre. His has a "lighter feel" to it then mine does for some reason. Little more flex in the frame on rough ground perhaps. But as far as cut it does just as well as mine and I believe the transmission is essentially the same K46 as mine, just a newer version of it. He does have a larger Briggs single cylinder engine where mine has a Kohler. I do prefer the older style reverse pedal on mine where you press it forward. His reverse you have to sort of press into the foot pad. One thing though about buying from a dealer is if you have any problems they'll tend to put you (being their own customer) ahead of the box store purchased units. That is worth something when it is raining everyday and your main mower is out of commission.
What is the terrain of your yard? Hills or fairly level and smooth? That is one thing that can determine which is better for your needs. Rough ground or hills you might be better over the long run to step up to a model with a more stout transmission.
I don't know if I would go so far as to say the X series is commercial grade. I have an LT150 which I suppose one could say is the predecessor to the X series. My uncle has and LA model he bought last year for about half an acre. His has a "lighter feel" to it then mine does for some reason. Little more flex in the frame on rough ground perhaps. But as far as cut it does just as well as mine and I believe the transmission is essentially the same K46 as mine, just a newer version of it. He does have a larger Briggs single cylinder engine where mine has a Kohler. I do prefer the older style reverse pedal on mine where you press it forward. His reverse you have to sort of press into the foot pad. One thing though about buying from a dealer is if you have any problems they'll tend to put you (being their own customer) ahead of the box store purchased units. That is worth something when it is raining everyday and your main mower is out of commission.
What is the terrain of your yard? Hills or fairly level and smooth? That is one thing that can determine which is better for your needs. Rough ground or hills you might be better over the long run to step up to a model with a more stout transmission.