Yes and no...
I bought the frame only for £5750, and have transferred all of my existing bits.
I think maybe at £7000, the Comp might be better value as you get a whole bike... and there may be some bits that you want to keep.
Even though I'm transferring parts off my existing bike, I'm still likely to be buying a T-Type Transmission (about £1500) and a new wheelset (about £1900).
According to the forum, there is going to be very little value in selling my old SL frame - so I'd maybe have been better with a Comp and rebuilding my old bike with the spare parts and being able to sell it as a 'bike' rather than spares? I don't like any of the Comp colours, so that wasn't really any option!
I'll get something back for the frame, my carbon SL1.1 cranks, XX1 AXS derailleur, XX1 cassette / chain... and I'll keep my old wheels.
Overall, the upgrade will still end up costing me about £6.5-7k though!
On another note, when the prices / specs were leaked, I spent 30 mins pricing up all the parts to build an S-Works to the same spec. It's not the spec I would personally want, but it came to about £11k if I remember correctly.
There's definitely a saving there if you're prepared to order the parts in and build it up yourself. I'm sure I could have got a lot of the parts cheaper if I'd shopped around too.