Tv ethos are fabulous but expensive.
have a look at eyepiece comparisons, then prowl the classified.
I have TV & ES being used in 10 & 16 inch dobs. Both are good, I like the wide field. Also have 3-6 zoom TV and while it is good, i think non zoom is better.
Best you can do is view through both before buying, a local astro club maybe.
http://www.svenwienstein.de/HTML/es_...m_English.html
The cheapies that come with scopes won't provide the same views as either ES or TV.
Good luck.