As far as I know, the only difference between Soniclean VT Plus and Galaxy are the color and warranty.
Soniclean Galaxy vs VT Plus
images from manufacturer
The VT Plus has a white front shell while the one on the Galaxy is black. And there is more silver color on the base of the VT Plus while the Galaxy has a mostly black base.
The VT Plus carries 3 year motor warranty, 1 year parts warranty, lifetime belt warranty; while the Galaxy carries 5 year motor warranty, 1 year parts warranty, lifetime belt warranty.
Same things they have:
Sonic cleaning technology;
Lightweight: only 10.5 pounds;
35 foot power cord;
Jam Protection Feature;
Sonicfresh fragrance dispensing system;
SEAL-TECH HEPA filter bag system;
High efficiency direct air paramagnetic motor;
Can lay flat to the floor;
Two separate modes for cleaning – one for carpeting, and the other for hard floors;
No suction control;
No hose, no wand, no tools included;
Bagged and include one bag ready to use;
No headlight;
Has side brush;
No manual height adjustment.
No swivel neck;
No brush On/Off.
If you know other difference between these 2 Soniclean upright vacuum cleaners, please comment below.