Basically, if you don't mind doing a little workaround to get it to run and you like strategy games where you summon monsters and cast spells and it doesn't bother you if it is from 2001, then you may well like this game.
Using Win7 64-bit initially the game kept crashing every 2 minutes so I checked the Community and learned to get it to run you need to run the game directly from the exe (default: Steam\Steamapps\common\Etherlords\Etherlords.exe) rather than hitting Play on Steam. You will also need to use the following compatibility settings on the exe: Disable visual themes, Disable desktop composition, Disable display scaling on high DPI settings, and Run this program as an administrator. Fortunately if you do all that you can then make a shortcut and not have to go through all that trouble more than once.
Anyway the game itself is complex but fun, it is like combination Turn-Based Strategy and Magic the Gathering. You have a base to defend and you can summon heroes who go out on the map to explore, fight, and capture to increase the variety of resources you have (the strategy part). The heroes in turn engage in battles with monsters or other heroes they come across, and the heroes do so by summoning their own creatures and casting spells from the spellbook you have them set with (the MTG part). They also get XP and levels from the fights in order to gain new skills.
Things get more complicated there since beyond the basics, you will need to purchase higher level spells from shops you find on the map but to do so you will need certain resources, of the specified varieties for the spell. Not only that but you will also need resources purchased at a different shop in order to even cast the spell in battle. That can make it a little frustrating since you might get a really cool new spell but not have the resources to cast it, or you may run out after using it a couple times. The battles are fun and fast-paced enough to keep it interesting and there is even an option to auto-battle if you feel impatient and the AI is decent enough to win unless you are at a disadvantage, and of course you can resume control at any time.
Some things you may not like, tooltips don't appear by hovering but instead by right-clicking so get used to doing that a lot. The tutorials consist of just blocks of text that appear the first time you click on something new and you will probably learn more by doing, or through the right-click tooltips. The camera is not always where you want it to be in battles and the default view has the minimap upside down so that was strange. Resource management gets in the way of enjoying new spells sometimes. The enemies are unfairly advantaged in that they do not seem to be as limited as you in their spells/resources. Also it's an older game so don't expect super graphics, but I will say the number of different monsters is cool and they look decent.