vs
The RRR on Seismic Assault is kind of scary. Molten Vortex also requires heavy red, but it can function on RR. It's more expensive in total at 3+ activations though, which is where you want to be. Thoughts?
Seismic Assault, no question. Vortex seems easier to play, but I've found it very awkard in practice.
1. Seismic Assault has one hurdle: You need to pay RRR once. After that, it's pure gravy. You can slap it down, drop two lands to get rid of a threat and keep working on.
Vortex keeps that hurdle every turn. Paying RR every other turn to use it is a bigger requirement than it appears. Often, it makes you choose between using it and casting other spells. And that's very annoying and makes the card much weaker.
2. Vortex is very colour intensive. Let's be honest, the difference between RR and RRR once on a card like this is very small. I haven't had a harder time playing Seismic Assault than I have playing Vortex, despite what it might seem.
3.
Vortex is not faster. In my experience, you don't want either of these cards when you are curving out. The reason is simple: If you are throwing away lands, you cannot curve out. You don't want to throw away your mountains if you want to play them.
I mean, you are playing Lands!
4. Both cards are parasitic. No, you are not going to play Vortex in aggro because you have better things to do than pay 3 cards and RRR to deal 4 damage.
Vortex keeps the hurdle every turn. And there are many turns in which paying RR is in direct conflict with doing something else. You may need those mountains to play a creature or play Life from the Loam. There are many times in which you could activate it but shouldn't be
Note that I run 20 Fetches, 20 Duals and 5 Canopy lands.