I don't have a Premiere but I do have both a Theatrum (spinet) and an early ('61) Rialto K (console) and I love 'em both. Great vintage analog sound, nicely built and finished, reliable and easy to service. The Theatrum has both the traditional tabs as well as drawbars (selectable by manual with pistons) and a very, very nice piano. The Rialto K has individual tone generators for the Tibia's and a separate set of divider style generators for the main non-Tibia voices. Seems to create a richer overall tone. According to the information I've got the Premier uses a similar tone generation system. I'm very happy with both of my Gulbransens. Since the model you're looking at is a console the information I've got says that it's either a model number 1154 (1967 vintage) or a 5118/5118-1 (1972) vintage. Unless somebody recognizes the difference from the pictures you would have to ask the seller for the model number to pin down the year.
I think that "Realistic Pipe Organ Sounds" is a requirement that your going to have to balance between your ears/taste and pocketbook. My humble opinion is that you'll find some good Tibia sounds and sometimes strings in these old analog instruments but you're going to have to go up quite a bit on the price to find something that's going to give you a reasonably well rounded theatre pipe sound unless you start to add some virtual pipe sounds a la Miditzer. I haven't heard or played the Premiere model but I'm sure there are folks on the board that can give you some first hand feedback on it. You can probably find something cheaper (my Hammond H-133 was a freebee) but I've liked all the older Gulbransen's I've ever heard.
I see also that you mentioned full size pedals. I believe the pedalboard on this Premier is a 25 note, flat, radiating unit -- works for me with what I play but it wouldn't satisfy you if you're planning a serious pursuit of classical works.
If it's close by I'd suggest you take a look and listen