Neither is going to be more beneficial than the other in the algorithm. There might be an indirect impact where it's easier for a user to type without the dash and using .com, but the domain itself isn't going to make a huge amount of difference to the search engine.
If it looks ridiculous without the dash, then keep it in. If it is fine without, then consider adding it.
With net/com, I'd always go for com where possible. Again, probably no direct SEO impact, but users are more likely to assume com over net