Honestly, this is one of my favorite series of games. I'm a bit of a medieval fanatic so I know what I'm saying when I tell you that I van definately recommend this collection!
The original Stronghold is the best. While old, the game mechanics are still quite impressive. Like any Stronghold game, you basically build your castle the way you want while simultaneously managing your stockpiles, funds, and hundreds of ungrateful peasants. You need to keep them happy, for the most part, but stronghold one has more to offer: you can also use fear to terrorize your subjects into submission! This, imo is the best way since if you can keep them both happy but intimidated, they will work much harder and produce more resources. Stronghold 1 imo is a 10/10!
Stronghold 2 is basically like the first one but with 3D graphics and a really annoying yet fun crimne system. Unfortunately, they completely got rid of the fear factor stuff and replaced it with crime which was a terrible mistake, FACT. However, Stronghold 2 is still tons of fun and to this day is still one of my favorites. Castle sieges are where this game shines as combat is a bit more realistic. Knights can no longer bring down castle walls as they could in stronghold 1. I give stronghold 2 an 8/10!
Stronghold Legends is imo the weakest of the franchise. It's an extremely dumbed down version of Stronghold 2. There is no crime or fear factoring and its just way too easy. Un;ess you completely suck at these kind of games, you will never see your happiness rate drop below 99. The only things I think are good about this game are the medieval mythology setting and the map editor. Imo, Legends gets a 4/10.
All in all, this collection is great! Hope this review helped.