Wanted to cross post this here too, see anyone's thoughts.
Given the price, and the fact that enchantments don't stack with the other runes and glyphs, it makes them a tough sell. Add on to this that most enchantments are quite underwhelming, and it doesn't really make them worth it in the end.
Having said that, if you have the money lying around, there are some decent enchantments. For example, Invigoration increases your damage up to 50% as long as you are at full health AND regening health. Depending on how fast you are regening, you can keep dealing an extra 5-10% damage with every strike. If you wait longer for a strike, then the damage will increase even further. The increase effect only lasts for one strike, and then it restarts the build up. Would have been better if the build up lasted for 10-20 strikes before starting again.
Replenishment is a neat little runeword that after every sign casting and an adrenaline point, gives your sword the spell's attribute. For example, after casting Aard, your sword will have an Aard attribute which will stagger an enemy when you strike it. Quen-sword will heal 50% of the damage dealt to the enemy. Fire-sword will deal burning damage in addition to your normal damage, which can be quite a lot against non fire resistant enemies. It only lasts for one strike though, and it requires an adrenaline point. Would have been better if it lasted for maybe 5-10 strikes, and didn't consume an adrenaline point.
Severance is also fun as it increases your Whirl and Rend range. This is the one that I personally use on both Steel and Silver. The utility of this in battle is more useful to me than some extra damage.
With glyphwords, the ones that change your weight class have potential. But these are currently bugged, so best wait till future patches fix them.
The rest of the enchantments are quite poor in my opinion. What the devs should do is at least make these enchantments stack with the other runes and glyphs, and also make the effects global. So, having one Severance on one sword should apply the effect for both swords. Then these would definitely be worth all of the money.