In case you're serious:
- if you're diving in dark muck (caves, wrecks, etc.), you'll want a bright backlit screen.
- If you're doing deco dives you don't want a "recreational" DC: they will compute you a deco schedule, but it will be suboptimal at best (and with multiple deco gases: useless). Arguably you also want a ZH-L DC rather than a Suunto Eon.
- If you want air integration, Vyper Novo is about the only option under $700+ price range.
For any of the above requirements a Shearwater is a perfectly good choice and is not significantly more expensive than the alternatives.