Groudon moveset

Groudon with Solar Beam has many alternatives; Groudon with Earthquake does not. Ground is great for soloing Gengar (especially with its bulk against the hard-to-dodge Sludge Bomb). Expect future generations to introduce good Electric-type defenders (like Magnezone).

I use my Earthquake Groudon from time to time - vs Electabuzz, Manectric, Aggron or Gengar (6th slot anchor) for example

I would never use it if it had Solarbeam, since I have 4 Level 40 grass attackers and like 12 being 34+

Groudon is king in one thing and that's ground.
Solarbeam is only an option if you somehow couldn't get a good enough grass collection together.

I have it with EQ, because my grass team is good enough that I don't need a SoB Groudon for anything and FP Venusaur is better for almost anything. If a situation like Blizzard Kyogre happens again, I'll consider TMing back to SoB.

A potential future use will be to counter Dialga, which is only weak to fighting and ground. Machamp will have better DPS, but Groudon will likely have the best TDO while still putting out respectable DPS.

For all the above reasons, especially solo Gengar, my 100% Groudon is Earthquake. Have an 82% SoB but don't use it much. Prefer Exeggutor and Venusaur in that role.

For the longest of time I've kept mine at Solar beam since the blizzard kyogre.

I use it as a sun boosted gym attacker from time to time so solar beam is better in that regard. It is essentially a confusion exeggutor you can dodge with and has slightly higher bulk, although probably lower DPS.

Either move is excellent to be honest. Earthquake gives you sizable gains in a select few matchups, while solar beam gives you modest gains for a wide variety of matchups.

I have an Earthquake Groudon good vs. Rock, Poison and Electric..
I don't need a SoB one becoz I have enough Grass attacker...

In clear weather I soloed a Discharge Jolteon with a so-so level 30 EQ and 4 so-so level 25 EQs. After that I brought my better one to level 38. Stalled out on maxing, but feel it is pretty good to have

There are so many good grass attackers in the game and so few good ground attackers. Groudon deserves Earthquake. (And Earthquake deserves a buff like Sky Attack got)