I started using the Funambol v6 push email client for JavaME, which has been released in alpha a few days ago (it is open source, GPL, available on the ObjectWeb Forge), and it blew my expectations.
I know I am biased, but compared to Gmail Mobile the experience is totally different. I am not talking about the client being better (although I like it more because it is simpler). The big difference is that I am really using it, while I used the Gmail Mobile client just five times after I downloaded it...
Because I have SMS push...
What does it mean? It means that every time there is a new email on my Yahoo account (yep, we are not locked to Gmail ;-) a message appears on my RAZR and the phone beeps. From the cover, I can see it is a Funambol message. I open the phone and it says "do you want to open Funambol?". I say yes and I get my email downloaded from the server.
With our portal (now in pre-alpha, we showed it at 3GSM, come and see it at CTIA at the end of the month if you are interested), you get the client pre-configured on your device. No typing necessary. Just click on a message and you are done. The app is on your device. Your email appears magically.
I count 8 clicks on my T-Mobile RAZR phone to open the Gmail Mobile client... I have to go through "Fun&Apps" (the icon looks like a movie!), then "Games & Apps" (the icon looks like a joystick!!) to get to it. What are the odds that 95% of the population would never find the client once downloaded, because to get their email they have to be willing to watch a movie with a joystick? HIGH, VERY HIGH.
Instead, you downloaded the Funambol client. You lost it somewhere in your phone (it goes where GMail Mobile goes, there is nothing we can do about it...), but then someone sends you an email. You get a message, you click on Yes and your Funambol client pops out. You are using it. And you will keep using it, because you are going to get more emails.
What about battery? No difference: SMS reception is active on your phone anyway.
What about the cost? Well, that's a different ballgame. But we are not proposing this to enterprises (although it would be nice to try a price comparison with a BlackBerry monthly fee...). We give it to mobile operators. They bundle it for you, poor consumer, in their offering. You won't see the cost per message.
Up to a few weeks ago, I thought SMS push was a cool feature for a killer app. An important one for usability purposes. I just found out not having is the killer of the app. Push is the key for JavaME email. Without it, there is no consumer email. At least, not on Java phones, which are just 1.5 billions out there... Hello consumers, email is mobile and it works for you :-)