Hi! Where have you been?! This board has been dead without our regulars!
Of course, you know how I feel about the PSR-E433 -- I've had mine for almost 7 years now. I could've upgraded, but I just have not yet felt that there has been enough "there" on the E443, E453, and E463 for me to make the switch. The big thing, for me, is the DSP. But the other upgrades, such as the 48 notes of polyphony, tunable scales, and sampling, while worthwhile features and would likely be important for certain buyers, are just not that much of a big deal to me. And the other thing I like on the E463 (and possibly also the E453), which is the ability to add reverb and other effects to the drums and styles, also has the significant drawback of not memorizing those effects settings when powering off and on or switching to a different style. And while I haven't heard them side by side, overall, I don't hear a significant sound quality difference between the two, except when using the DSP effects that are not available on the E433.
Since you already have some keyboards, let me also throw another suggestion out there -- You can get a small synthesizer to add to your set-up, which is what I just did. I bought a Roland GAIA SH-01, but there are numerous options for synthesizers today in the $300-700 range. For me, it really adds a whole new dimension to my sound options and playing, allowing me to do various effects, portamento, and orchestration that I didn't have before.
This is what I use to play and record music on now (just click on the links to see the images)...
https://app.box.com/s/mz81amwvxbh3bqs4i9lod9ixuwafxrudhttps://app.box.com/s/4duqwnv816xxgj5poz53qjp9en51lhlpIn the first image, illuminating LED's are switched on, while in the second image, they are switched off.