ooma is far superior voice quality (near landline quality), can power your complete house phone, if you can find a core system( radio shack is the only place you can still find a core version, which including hub and a scout), no fee no tax for life for basic service (caller id and voice mail only, no call forwarding), up front equitment cost is $250 retail, or on sale 160-180 if you can find one..the hub only verion ($119 on sale) or telco ($180-240) version cost about $3-4 a month for taxes. you can port your old number in to ooma for $40.
Magicjack is soso voice quality( about cell phone quality), needs a decent computer to run with it, but for $20 a year or $70 for 5 year services, you don't expect a lot, free voice mail, caller id, call forwarding, 411 service, e-911 service. I only use it to call out at home, incoming calls are forwarded to my cell.
both not good on fax service. I use ooma at the office, magicjack at home.