The pitch bend wheel is a great feature, and is very useful when using sounds like guitar, violin, or any other instrument sound where the actual instrument being simulated can bend the pitch. And, it can be used to simulate a synthesizer portamento effect -- to an extent. But it's no substitute for an actual portamento function.
Check out some Classic synth leads, like the beginning of "Fooling Yourself" by Styx, the end of "Lucky Man" by ELP (Emerson, Lake, and Palmer), and the theme to the 1970's TV show, "The Rockford Files." There is no way you could simulate all of the portamento's sliding pitch between each note with just the pitch bend wheel. Additionally, manipulating the pitch bend means you are now using your left hand for the pitch bend wheel, and cannot use it to play accompaniment. If you're using auto-accompaniment, you might be able to quickly stab the necessary chord changes between actions on the pitch bend wheel, but it would be tricky. And if you don't use auto-accompaniment, then it's practically impossible. In that case, the pitch bend in this way would only be useful if you're playing in a band, where other band members are playing the accompaniment, or if you're doing a multi-track recording and recording the accompaniment separately on different tracks. Using portamento, however, is automatic and does not require you to take your left hand away from playing the accompaniment.
I use a Roland Gaia SH-01 synth in conjunction with my PSR-E433, so that helps take care of my portamento needs, not to mention the ability to create a wide variety of custom sounds not available on the E433. But it would be nice if Yamaha included some version of portamento on the E400-series keyboards. Even if it was just an effect "baked in" to some of the synth presets, like what Casio does on the CTX-700 and possibly some of their newer CTS-series boards. Oh well... Maybe on the PSR-E483!
