I have tested both and finally decided on the HT-E5500.
Differences of HT-E4500 for HT-E5500:
> Significant longer charging times (Tron Legacy: HT-E5500 under 10 seconds, HT-E4500 about 30 seconds)
> No WLAN, only "wireless ready"
> Boxing though with metal mesh, but without clamping connection to the boxes
> No iPod dock, USB port only
> No touch operation on the display, "hardware" buttons for Play / Eject etc.
Subwoofer, remote control and interface are identical to the HT-E5500.
The price cutting is about 60 EUR (HT-E44500 approximately 240 EUR, HT-E5500 about 300 EUR) - from and to the HT-E4500 is still to get into a Shrek-Edition; Here are then all four Shrek-parts on BluRay in 3D (only in 3D) case, value 40 EUR: price difference then 100 EUR.
On the part of operation and sound, I may find no significant differences.
I have yet to HT-E5500 decided (see relevant review).