Magic the Gathering: Rate my Esper Control Deck?

I'm sorry, it's not very good, at least not in a competitive format. (It's fine for casual play if that is your intent.)

First, Rupture Spire is inferior to Reflecting Pool, which you should be playing four copies of if you really want to optimize your deck.

Path to Exile is a format changing card and if you have a way of playing it, you should play four copies or none at all.

Master of Etherium is another card you either play four copies of or you don't play at all because it either has synergy with your deck or it does not. It obviously does for you, so you should play four copies.

You should also be playing Etherium Sculpter. It makes all of your spells cheaper, which is really important to Esper decks.

Tidehollow Strix is pretty good in limited formats, but it's not really that good in constructed, so you should probably cut it. Instead, you should play Bitterblossom. I understand your deck doesn't have a fairy theme and Bitterblossom is not an artifact, but its just THAT good.

Much like Path of Exile, if you can support Bitterblossom you play it, because it wins games.

Executioner's Capsule isn't very good. Too many black creatures and multicolor creatures with black in them that will make the capsule a dead card. Instead, you should be playing Courier's Capsule for card the card advantage.

Agony Warp should be four copies. Countersqual should probably be four copies. Esper Charm isn't as good as the cards it competes with and should probably be cut, even though your deck has an Esper theme.

Not sure if I would run Cancel. Most of the time you will be playing cards on your turn and won't have three open mana to bother counterspelling your opponents threats.

I'd cut Jace. He's really not good unless you are planning to mill your opponent. Otherwise, he's a draw one card for three mana, and then he dies to something. Many other draw spells are more efficient.