Speeds are limited on the plan i'm on apparently which is the $50 one. The $60 plan should be faster.
When I said I just use the APN I meant the same settings you have above but the rest of the fields are blank. So mine looks like this:
Name: H2O Wireless
MMS Proxy: 184.108.40.206
MMS Port: 80
MMS Type: default,mms,hipri,supl (no space between then)
Speeds I haven't tested as it's HSPA+ but prolly limited to 7.2Mbps speeds or something. The $60 plan is "10x" faster, whatever that means.