I'd buy Acustica Audio's Taupe. Mainly because it's an amazing 'colour' making plugin, tape-emulation or not. Taken as whole, it can impart so many colours. I think the combination of all the tape impulses with the EQ and the compressor is a master stroke as it really helps to add a lot of analogue mojo to the mix. I've been demoing it for some time now and I'm desperately trying to talk myself out of buying it.If you buy a tape vst today.
However, personally, I want several of such plugins at my disposal, as each one provides their own unique take on the 'tape' sound. In fact, I'm less concerned if a plugin nails the tape sound and I'm more interested to find out if I like the 'colour' it's adding to the tracks or the full mix. Whatever this 'colour' may be. For example, I found Airwindows ToTape5 a superb 'colour' maker, which in one situation worked amazingly well in combination with Taupe. The two, used very subtly, gave me a superb, larger than life sound.
I'm currently testing Voxengo's new update to the CRITIV Tape Bus plugin, and it seems to be an amazing 'colour' maker as well. Some very nice options there.