First off -
http://www.head-fi.org/t/596233/buying-portable-or-in-ear-headphones-seeking-guidance-dont-start-a-new-thread-ask-for-advice-here
(but I see from your post history that you've at least posted on the thread before, so assuming making a new thread is a conscious effort rather than just missing this one)
Regarding the build on the higher-end Shures - I really detected little to no difference. Sure the plastic on the 215s weren't as thick, but the connectors and cabling still looked quite similar, if not identical.
In terms of alternatives, we're still not sure what sort of sound you'd want - simply wanting "better" is rather vague and subjective. Do you want something with a similar signature as with the Shures, or something entirely different? What are your sound preferences? What do you prefer in terms of comfort or isolation?