Yes believe me, if you have the money, a crate engine is the way to go. Everything is brand new, works right, and is put together so that all the parts work together perfectly. It's just that crate engines are expensive if you want something that is actually performance. Even a 350 with like 330 horse fully assembled (not including all the accesory pulleys or brackets) is like $3,700.
If you can afford a crate, though, then that is the best route for compatability.
I'm building my own for a few reasons. For one, it's the best learning experience you can go through. Not only will I know how to assemble and modify everything in my engine bay, but I will also have a full and intimate understanding and knowledge of every little piece that is in and on my engine. Two, it's a lot cheaper than buying one (that is, of course, if you are using a lot of reconditioned parts like I am). And lastly, it's fun as all hell.