Really depends on what you're trying to go for. If you're doing sound design and setting up FX cues for theatrical event,
headphones are deceiving because they misrepresent the spatial effects because in a live environment your left ear also hears what your right does and vise versa, whereas
headphones isolate your left and right ears from each other. If mixing FX or studio work is what you're going for, you're better off picking up a good pair of reference monitors than a good pair of
headphones. Also always something to be said for being able to stand up and walk around
through your mix, which you can't do with
headphones.
If you're trying to record on-location and want to check your levels, then over-the-ear
headphones or higher grade in-ears are better. I wouldn't go for any in-ears below
Shure SE315's though. The 215's are garbage. At the 215 price
point you're paying for isolation, but you're not getting enough LF content and the resulting audio is a
bit aggressive for my taste compared to my 315's, which have been my everyday
headphones for the last 5 years. As a general rule though, if you want to get in-ears equivalent to over-the-ear
headphones, plan on spending 2-3x over comparable over-the-ear style
headphones. Isolation and small form factor comes with a cost. If you're budget is limited today, you'll get more bang from the buck on
conventional headphones.
Long-term, I would
pick up a pair of in-ears though. Shouldn't be your highest priority now but in everyday life having isolation
headphones will help save your hearing over the length of your career when you're working, at the gym, walking along a busy street, waiting for a concert to start, or mowing your lawn. These are the kinds of things where over-the-ear
headphones aren't
practical to carry with you everywhere. It's an indirect avenue toward retaining your ability to do your job effectively.