G12, G15 or new lens for T2i

I use Canon crop cameras and was thinking of the G12 or G15. Is the G15 worth the extra $120 for F1.8-F2.8?
My thinking was that the camera could be handy for travel, or for instances (late in the day) when I don't want to carry the T2i with the kit 18-55IS.
Will I be able to see any difference between the T2i with the 18-55IS and the G12 or G15? I am interested in low light performance as well.
I have been using the T2i for travel, and wonder if I will be losing anything with the G series.
I do have better lenses than the 18-55IS, but they are heavier and bulkier.
Any feedback would be appreciated.
I have the 24-105L and the 12-24 Tokina. I am missing a one lens solution for travel.

Big sensor always beats small sensor. Go to the DPR image reviews for the G15, which includes the G12, P7700, and RX100. Change the RX100 camera to your T2i using the drop down selection, then change the ISO to your desires. This link is to the RAW results, but the JPEG results (normal and high) are on the preceding pages of the review.

http://www.dpreview.co​m …ews/canon-powershot-g15/6

Dennis

Dennis that's very helpful!
Great resource.

Thanks. I see clicking on the link I provided now takes you to the Introduction, while the RAW comparison is on page 12. They've been adding to it.

Dennis