I have the heavy 830 Bernina, and a Horn cabinet with a lift. I usually sew with my Bernina recessed in the cabinet and the white slide-on table that came with my Bernina. The slide-on table slides easily off the machine and to the left over the top of the sewing table. It took a little trial and error adjusting the lift, but once it was adjusted, it works well.
I when I quilt a large heavy quilt, I like quilting on the big flat surface at table height. The quilt slides freely. I also like sewing on a a big flat surface at the right height for me ergonomically. That is important to me. Did your 750 come with a slide-on table?
I don't have any trouble changing bobbins underneath the slide-on table. There is a clear plastic window in the white slide-on table that I can see the bobbin area through. I reach under the front edge of the cabinet and open the bobbin door of the machine. Then the 830 screen automatically switches to a bobbin screen, with a little icon at the lower right that I can touch as an option to reduce glare off the clear plastic window if I want. It was a little awkward at first, but it is easy for me now. I don't even think about it.
To oil the bobbin area, I slide the slide-on table off to the left on top of the cabinet. It just takes a minute for me to oil the machine.
I don't know if the 750 is as heavy as the 830, but if it is, be careful if you decide to buy a cabinet with a lift. The first cabinets that came out for the 830 were large enough for the 830, but were not sturdy enough to handle the weight. The heavier machines need a sturdier support.
Hope this helps,
Judith