I disagree. I personally loved the last 2 episodes of the series, I didn't think it ruined it at all. I watched EoE afterwards also.
I suppose it depends on what it is about Evangelion you enjoy.
If you watch it for the fact it portrays Shinji's struggle to understand his place in the world, build relationships with people and come to grips with his own self while surrounded by quasi-mythological psycho-babble then the last episode is good.
If you watch it for the fact it features weird alien monsters being destroyed by huge Bio-robots in a variety of violent and explosive encounters then EoE is a better bet.