I can happily say that DD is one of the best games I've played :)
The community is amazing and have extremely 'newbie-friendly' tutorials (ans is therefor, in my opinion, a better game than DDE)
The controls are easy to get used and it's up to you how you'd like to place your towers, depending on your characters/stats.
One thing that is a bit bothersome is that you basically need to buy some of the DLC characters to get the full experience, however, you do not need to buy most of the maps since you can join certain maps even if you haven't got them.
With over 8 heros (4 are given to you for free) it gives for great replayabiliity :)
The game is definiately worth it's money and if you happen to buy it while it's on sale you've made a bargain!
(A negative point is that equipment (aside for weapons) do not show up on your character. You can however unlock skins and color-customise it.)
I've played the game for nearly 300 hours and I still haven't experienced everything the game has in store :)
(Do by all means send me a message if you want tips in-game or if you'd just like to lvl)