They are not able to provide long codes (10 digit phone numbers) for messaging in the States, but they can use long codes for messaging internationally.
In the states you're limited to Short Codes, but they do offer MMS support, which one-ups Twilio. I believe they also have a higher send rate, but I don't remember the specifics. Ericsson also has mobile payment support (charged to the carrier), where Twilio does not.
My research was specifically for messaging, but there is voice functionality as well.
Overall, Twilio is a lot more developer friendly. I think I waited something like two weeks for a callback from Ericsson, which would never happen with Twilio. But if you really need international phone numbers and advanced features, take a look into Ericsson.
I use Twilio now, but I don't use Ericsson yet. Chances are my product will end up using a combination of both, but the nature of every product is different so do what's best for you. Twilio can text/call internationally, but not with local numbers, which I believe makes the cost quite high on yourself and your users. Apparently there are also other solutions I haven't looked into yet (see other comments).