I prefer opt for a few reasons: with 12 fetches scrying 2 cards to the top and still trying to use your mana can be awkward. Opt is also better mid to late game since it gives you more looks at a card right now rather than setting up future draws. The instant speed to bluff denial is also relevant.
That being said I don't think it's objectively the better choice, more personal preference than anything
How are you doing with opt, are you running 4/2 split with visions or vice versa?
After experimenting with the 18 lands and 2 cantrips list I've gone back to 19 lands and run the full playset of opt right now with no visions. I'm really liking the current setup. I got more value out of having the additional cantrips when I used to play pyro in the board but without them I feel it creates a bit too much air in the deck and I'm spinning my wheels more than I would like. If I was to go back up to 6 cantrips (excluding scour) I would most likely favour opt as a 4/2 split personally
what would be your reason to have opt over visions
Here is my list,
4x Street Wraiths
4x Snapcaster mages
4x Death Shadow
2x and 2x of delve creature
1x Liliana of the Veil
4x Fatal Push
2 Lightning Bolts
1x Terminate
1x Dismember
2x Stubborn Denial
4x Visions
4x Thought Scour
4x Thoughtsieze
2x Inquisition of Kozilek
1x K-Command
18x Lands
Please let me know what you think.
I use to run an esper version, it felt very mediocre compared to grixis, the esper shell does give you solid pieces but it does not finish games quickly enough. For your list I can see a removal of opts and putting the fourth serum visions and take out on stubborn denial to add two Inquistion of Kozilek since you want to make sure the coast is clear and then land your threat. It is very different from delver and the charm I did like as a surprise effect if the did not know about it.
4x Street Wraiths
4x Snapcaster mages
4x Death Shadow
2x and 2x of delve creature
1x Liliana of the Veil
4x Fatal Push
2 Lightning Bolts
1x Terminate
1x Dismember
2x Stubborn Denial
4x Visions
4x Thought Scour
4x Thoughtsieze
2x Inquisition of Kozilek
1x K-Command
18x Lands
Please let me know what you think.