MS/E Rhydon a decent defender?

Maybe by pure CP for your area but in general no.

not a bad attacker but main defense value is CP

you can also try and slot him between two gyrados which would force a change out of jolteon or make the attacker use an eggy ( a lot of gyrados have dark moves though). At least one rock move is usually better though as then it might make dragonites suffer a little (before finding the gyrados is DT/crunch)

It is a terrible defender (destroyed by Vaporeon or Venasaur, not to mention I just killed one with Azumarill today) but with the high CP they are very common in gyms. So if you are in need of a high CP defender then may still be worth maxing out because if you can get into the top slots in a high level gym, a Rhydon will still earn you coins.

i say max it if the IV's are good (i.e. >89%). mine is almost maxed for my level (3048CP at 35.5Lvl) and gets great gym placement in my area. somehow it also has 2 battles won, so i love showing it off!! but i should say i think this is very odd given that every MS/E Rhydon i've faced in a gym has been easy as shit to destroy. ah well, some mysteries i'll just leave alone haha. again, i say max it based on my personal experience!

save candies and dust.
I have 98% IV rhydon with 3k cp but it is not a good defender, you better save it for higher IV rhyhorn or rhydon or for dratini/lavitar.

There's blissey and snorlax, then there's everyone else. I do think that Rhydon is the best of the rest; so I say,"yes."

no

Earthquake is so easy to dodge... it really took any "oomph" of it being a decent defensive move.

Stone edge on the other hand, comes out of almost nowhere, and unless you are a very cautious and calculated dodger, it is easy to get hit by it. Not to mention it is super effective against flying, which hits gary and dragos hard

MS/E or MS/SE are both decent def moves for Rhydon. Although I will agree it's not the "best" defender, based on its max CP it is one of the 'best' defenders in terms of gym placement and coin revenue at the moment.

Max it out and stick it at the top of a gym like everyone else and enjoy. :)