That set is only 3/8" drive: it is light-duty. There is no reference either to manufacturing process (they need to be forged) or alloy (they need to be chrome-vanadium), so all I am left with is my experience with Stanley tools, and that experience has been that they are not of professional quality - in some cases (screwdrivers) by a very wide margin, in other kinds of tools by a smaller margin. As I understand it Stanley bought Sidchrome as a premium-priced brand, but have downgraded the Sidchrome products now that production is in South-East Asia. The Stanley brand is positioned far below the Sidchrome brand of course.
Another reason I would not choose that socket set is that it has a full set of extended ("deep") sockets, which you seldom need, so you are buying nearly twice as many as you require, and paying for all of them. Further down on that same web page there is a set of half inch drive Stanley sockets for that same price (but without the "deep" set accompanying it.) So far as working on your ride-on is concerned, that 3/8" socket set would probably be adequate. If you ever move on to even a small tractor or car, Stanley 3/8" drive sockets just aren't where it's at. You could do most of the work on a car or small tractor with the Stanley half inch drive set, though.
I am not suggesting that you pay premium prices for professional tools - you won't use them enough to justify the expense.
