Re: [NathanL100] S3 vs. GTI ??
I may be talking out my ass here, but... I'd say go with the one with which you are most comfortable and current. I'd imagine that you can get the S3 to perform better in BASE, as you would in the air, but if you've only put in ten - twenty S3 flights and are still feeling it out, but have 100+ GTi flights, I'd say BASE the GTi until you've got the S3 nailed.
If you haven't flown the S3, know that it is an entirely different beast than the GTi.