Now there has been a debate over a few things and I hope this helps settle it. Note: This is my opinion and is in no way intended to tell YOU what to do.

First off lets get something out of the way.
1.) The game is in beta.
2.) There is not a non-failing equipment upgrader (Maybe someday).
3.) There is a limited number of useable mon types.

The upsides:

Good equipment is very useful if you are running solo without your mon consumed or summoned. They look cool.

Eudemon can help you in any number of ways, from def to attack. A good eudemon can help you fight monsters well above your level. Eudemon looks cool.

The downsides:

Good equipment is expensive, if it breaks the special repair requires ore as well as gold and this can be time consuming. Even making good equipment can cost alot two sockets runs you 13 red stones not to mention the 4 it takes to super it and the nine yellows it takes to plus it assuming ou dont fail.

Eudemon really dont have a major downside. Other than the fact that it takes time to level them and to work with them to get them to the way you need them to be its not really that bad.

Now for those guys who got rich when they killed that boss and got 5 red stones and a bunch of elites who want to look cool go for it and make your equipment and spend all your money to show off. For the rest of us who spend most of our time leveling I think we will stick with our eudemon and will in the end be better than you.

So have fun and whatever you decide good luck.