Upgraded Tower vs Regular one in Soulkeep

In Soulkeep every mana spent should be used wisely whether you could add two towers or upgrade the one that you have and when you could upgrade a tower don't hesitate to do that as a tower with upgraded feature is better than two regular ones.

You can upgrade tower for damage and also for speed and you could upgrade its range and when you have two choose between those I recommend to upgrade it for damage as its damageay increase up to 100% and this would help in eliminating fiends in a good way.

You can also upgrade for tower speed and this would help with some towers that has low mana to be used and at the same time it has a very high fire interval then you could upgrade it for speed to reach a higher level of the tower.

I do not recommend to have an upgrade for range as it would increase range much and it is better to have a towers with high range as inherited feature in it if you want that and then you could dominate the battle.