You will not regret getting the OS. You can research and compare engines at the top of this page under 'user reviews'. Unfortunately there is only one review of the Evolution .52, but there are many of the Evolution 46, [link=http://www.rcuniverse.com/product_guide/EngineProfile.cfm?engine_id=618]here[/link]. So the engine got 3.5 stars. Doesn't sound that bad, but when you read through the 52 reviews and see the people that gave it a one and a two, and complain about dead sticks, tuning problems, removing parts, etc. I can't imagine what is appealing. Poke around and read up on the 55AX, or ANY OS engine for that matter. I'm about to assemble my 6th plane, and every one has had an AX engine for power.

Of course you need to make your own decisions, but I just want to offer all the resources I can so that you make a good decision and are happy with it.
I have no personal experience with evolution engines, other than seeing one guy at my field with a few of them struggle; he has replaced two or three of them with other engines. I have also read a lot of crap that, in combination with what I've seen at my field, makes me never want one in any one of my planes. I have experience with OS, and strongly recommend OS engines. (and no, don't work for them, just very satisfied with products, service, and support).

Now this IS a beginner forum, and I am a beginner, so listen to what other people have to say about it. I can say that I've spent a lot of days at the field, have burned through 14-16 gallons of fuel this season, am about to build my 6th plane (5 of those planes are/will be still flying =) and have worked with some of the best precision aerobatic pilots in the country, so I am not just speaking jibberish here.

Bolt on wings are easier and take a little less time, and they look better (no rubber bands). Rubber bands will stretch and break saving you some damage in a crash, but the nylon bolts work OK too. 6 of one, half dozen of the other. I like bolts; no need to worry about strapping on 16 rubber bands, having them break, corrode, etc.