Monopoly without Mayfair and Old Kent Road? How will that work? Where is the fun in that? Winpolis uses hospitals instead of stations and different street names. After the initial shock, you will realise that this doesn't really matter. So it's actually just a matter of "so what".
Let's skip the detailed description of the well known 'buy – build – collect rent' concept. For such games, it is the details which decide about the overall quality: general playability, amount of options and changes or expansions of the concept.
The first point is quickly covered: Graphics look amateurish, but they are nevertheless very clear. The mouse controls don't need any explanation or even a manual – everything is completely intuitive. If you don't have four people around, the computer can take over the rest of the players. The AI is basically adaequate, but no match for human players on the long run. Monopoly will always be a game which offers most fun played with other human beings.
Only then, all the options concerned with buying, selling and trading of streets really make sense. The computer controlled players try their best to participate, but in the end, they will always lose out against the humans in these deals: The perfect strategy which almost guarantees success against the AI is to simply never give anything away, but only to buy the opponents' streets with money. As soon as you've got at least one street of each group, you've basically won the game, because you can effectively prevent any competitors from ever building anything. With the small earnings you get, you can then slowly buy one group after the next and start building yourself – soon enough, everybody else will run out of money. This game tactic would be impossible to carry out against human players, because they would never agree to such one-sided deals.
Therefore, even the usual excuse about using the AI for 'training games' doesn't really work, because playing against the AI is hardly comparable with playing against humans. It is still quite fun for a quick round, because even the outlook of winning alone can be motivation enough. The entertaining in-game texts, especially on the chance cards and some diversity through the use of trivia questions on some fields work in the game's favour as well: This is a very solid version of the board game classic!
Funny sidenote: The interest system used by the in-game bank is completely backwards; the interest rates for a positive balance are higher than the ones for credit under certain circumstances. I would love to be a customer there!