7x57 is a great caliber with very mild recoil but if Eland is on the menu I would personally want something with a little more bullet weight. But to be sure plenty of large antelope have been taken with the 7x57. Shot placement is the key. If you like the cartridge then get it and be happy. It will do what you need it to.

If you want heavier bullets then 175gr and you don't handload I think a 30-06 would be an excellent choice for everything and ammo is always available in a very wide variety of loads. It is kind of like the vanilla of rifle rounds though. If you want something different but still heavier bullets then I would look into the 300 H&H but ammo choices are much less then the 06.

If I were in your situation I would probably get the 7x57 as it sounds like you will mainly be hunting deer sized game and smaller the majority of the time. It is a fine round and will surely serve you well if you do your part. By all accounts it is one of those cartridges whose killing power is greater then its paper ballistics. If I were going to hunt Elk sized game a lot then I would go for the 300 H&H.

Check out this link on the 7x57;

http://www.chuckhawks.com/sensible_cartridges.htm

More info on the 7x57 here;

http://www.chuckhawks.com/7mm.htm

Regardless there are tons of bullet's in 7mm or .308 (300 H&H/30-06) for you to choose from so you wont go wrong with any of them. Hope this helps.