I'm 49 years old, I have gamed since playing Joust on the Atari, and HoMM5 is second only to the original X-COM games in my personal best of all times list.Yes, the graphics weren't state of the art, even at the time of release, but in my Nvidia 8600 GT that I used at the time they were fluid and looked gorgeous. Among the many, many factors in favor of buying it: Many factions, the long campaign and the many languages offered. The original manual was barely ok, but the community created the most amazingly detailed and beautiful manuals I have ever seen, google for them, they even come in many languages. Now, even in the easiest difficulty setting, the game can be very unforgiving in latest stages: I still remember how getting out of the underground world seemed an insurmountable task for me, even with frequent savings (darn dragons, the enemy had so many). All in all, it's a great value for any kind of money. I recommend buying it.
This game was my first adventure game in years, and was very interesting to play. All places you visit are very different from each other. The puzzles are mostly very logical, in very rare occassions I had to read an online guide to solve them ( one or two near the end, for instance). I highly recommend it.