Basis 2500, 2800 or Debut - which would you use?

They are all good. The Debut has the best overall Performance based on
its low frequency ability (it has to do with weight and isolation).
The Vacuum Option is very good, probably the best in the world (low
pressure, reliable, no - negative -influence to sound quality, top bearing,
good motor...)
Some time ago he had a technical paper what is done for what reason,
very clever solutions (the suspension for example).
In a way it is a tool for a record collector who isn't interested in any sonic
artifacts, instead it will show you very clearly what is on your records.
A lot of Audiophiles look for something they don't know, but they want
to have it. This is the reason why some many Designs are available and
all have their Fangroups.
I think, the Basis Design is for those who want a serious reproducer for
their music because they understand what is going on with it. Today, a
minority :-)
But I would buy it with a Phantom Arm instead of the Vector.

you are in the upper limits for me but I have a 2200 sig and love it, also have a 1400 sig in a second system. the 2200 has been a solid performer for years, dead silent and impervious to mechanical or airborn vibration.

In the 90's I was a visitor from a Dealer demo, he had 5 Turntables on a rack, some very expensive ones (Linn LP12 max, Clear audio, Simon Yorke, Transrotor and a cheap Basis 2001 with Suspension feet, Rega 250 with Incognito wire and a Miyabi Cartridge)..all Importers used their Arm/cartridge of choice used the same Frontend and Amplification + Speaker, all carts got 47kohm, no damping ...
This little Basis was so superior to ALL that a few Listeners asked for another demo because they couldn't believe what was going on ... others were 8x the price...

I agree with Syntax. All of the Basis tables are extremely well-engineered and built to very tight tolerances, so you really can't go wrong with any of the choices. The Debut's suspension system probably gives it a slight advantage over the 2500 and 2800 in terms of isolation, but I would strongly urge that you get the vacuum system with it. I've got an Ovation that I upgraded with the Debut's platter, bearing and vacuum system, it has worked flawlessly since I got it in 1991, it truly conveys the music and the vacuum is a revelation in flattening warped records. Only point where I might question Syntax is the arm choice. I have a Graham Phantom Supreme arm, which I like a lot, but I'm not so sure whether I would not trade that for the latest Vector if given the chance.