Great game indeed. Certainly the one you want to try.
Upgrade from 2D graphic to 3D was well done both on map and the town without losing too much of game's uniqueness. The game sounds great as well as the transition of the music from the town to the map is good, and they also well represent the race you are currently playing. My personal favourite is Elf's town theme by the way. Listen to it if you get a chance. It's just great.
Not much of change in gameplay in the fifth version, but they did choose to do the right thing as they brought back the unit upgrade which disappeared in 4th version for some reason. However, new mode of gameplay is a welcome addition, as it comes with a new instant duel mode. This mode lets you choose a hero with all units ready and jump into the battle against your friend or computer right away. You can either play 1 vs 1 or 3 vs 3 duel mode using either multiplay over lan or hotseat. While this mode is pretty awesome as you get to start pretty intense battle right away, but there are some balancing issue of one hero being too powerful over others. Also, if you are playing hotseat mode and if your hero uses fire trap spell, your opponent can see the trap when it gets to your turn, so those kind of spell can be quite useless.
After successful transition from 2D to 3D with great add-ons and a few annoying bugs, this is a highly recommended game for both die hard fan of old Heroes series and for those who never played these games before. With great graphic, sound and gameplay all added together, this game earns 8.5 from me.