DevilDude

I think there's a misconception about EE that's pretty prevalent. It is not overpowered compared to the other tekkit mods, truth be told you'll get more millage out of IC2 equipment than anything else once you've taken the time to work up to it. The combination of IC2 Buildcraft and Redpower2 can be stupidly overpowered in its own right if you're clever about using them together. Using RP2 to make an automated cobblestone generator and then hooking that up to a mass fab on a sufficient power source (try using the RP2/IC2 water mill array for massive amounts of renewable power) and you get just as much resources as you can generate with a big array of collectors, and the stuff you’re making is better. The first problem is ease of use, and the investment required. Building up using buildcraft/IC2 takes huge amounts of work. Large scale automated operations take planning and forethought, and no small amount of simple intelligence. Equivelent exchange on the other hand does not. It doesn’t take nearly as much space either, you can build a top tier EE setup in a fraction of the volume needed for doing similar stuff with IC2. The other major issue with EE is griefing. Because of the way red matter and dark matter tools are programed, bukkit plugins have problems tracking their use. This means they can ignore block protections and don’t show up to on trackers like hawkeye when an op tries to determine who did what. This is a huge issue for public servers and it’s understandable that most admins just don’t want to deal with it. Though there’s a fix for this in one of the stickies where someone decompiled EE and added tags so that bukkit plugins would work again. [/rant] To answer the OP’s request, the best argument I can come up with is aesthetic. If you want people doing interesting builds having EE opens up new avenues to design and function. As an example I’ll compare and contrast some of my own plans. Since about 1.8 I’ve been most interested in oceanic biomes and living in them, specifically building on the now deeper ocean floors. My builds tend to be functional, complete with biodomes, living spaces, industrial workshops and whatever else strikes me as cool. When I discovered tekkit, it just added a new dimension to these designs, the industrial concepts compliment the mostly tech inspired architecture I use in such builds. Doing IC2/BC/RP2 builds on the seafloor just fits, it’s awesome, but there are other builds that interest me. Before I started tripping on ocean life, I was interested in floating islands, but couldn’t work in the scale I wanted to. Various mods like the Aether mod and certain world generators were interesting, but ultimately I wanted to play in SMP so I could share my creations with others. Aether has yet to achieve SMP support, and I don’t have time to use a worldgen and run my own server so I shelved the idea. Since then minecraft has evolved, and so have my ideas. With the advent of jungle biomes and the increased height of world I can start thinking about building islands in regular worlds. Imagine floating jungle islands, volcanos with lava flows dropping down to oceans below contrasted with water falls fed by lakes. I don’t see an industrial park fitting into this, but Mayan or Khmer architecture would look amazing. To stay stylistically in line and still remain functional EE and possibly thaumcraft or its planned successor (if they ever go multiplayer) are my best bet, truthfully doing all this might not be possible without EE, or at least require massive stripmining that would disrupt the build. IMO the issues with EE can be worked around, and it opens stylistic options that can really add to a server’s diversity if managed right.

repeating what others have said, go look in the server forums, many of them will say if they have stuff to help newbies. further, lookup tutorials and let's plays on youtube, they'll give you ideas. Finally, familiarize yourself with the wiki's for the different mods, they'll be your biggest resource.

that's a version mismatch, check the box to manually set version in the launcher options and then choose whichever version the server's supposed to be on.