For what it is worth, from a technical standpoint, the MS 260 is an older design. It is considered a "pro" saw, as it has a split magnesium crankcase and a 4 bolt jug. But it is an old design as it has 2 closed transfer ports. Closed ports are better than open ports as far as performance is concerned. But new engine designs have 4 ports. The MS 361 is a 4 port, closed port design, with the softer anti vibe elements. It is a newer design. The MS 270 and MS 280 are not as new as the MS 361, but are newer than a MS 260 and are considered "occasional user" saws. The MS 270, 280 has 4 ports, but they are open, and it has a modular engine, not the 4 bolt jug.
So to make sense out of all this:
4 ports are better than 2
closed ports are better than open
a split crankcase, 4 bolt jug is better than a modular design, as far as serviceability is concerned
newer designs have engineering improvements over older designs, both comfort and efficiency
a pro design will cost more than a modular, occasional user design
So you have to decide if you want to spend the money on a pro saw, which will always be money well spent, or if you know you will not be cutting cords and cords of wood per year, then save some money and buy the home owner, or occasional user design saw.
The MS 260 is an older design, but well proven and absolutely an awesome saw.
The MS 270 and MS 280, with a little more displacement and HP than the MS 260, has a great feel to it and performs well, for less money.
It would cost you more to repair a MS 270, if you ever had to replace a piston and/or jug.
HTH