Clara, I'd also suggest you do your own search on the internet and look at a lot of various sources so you can make your decision based off of that. The few sources I posted were only a very small part of what I saw and anyone can of course look at one or two of them and just attack the source :).
The best way to make a truly informed decision is do some extensive researching on your own I think.
In the end, personally, I'd rather stick with funding my local shelter. There is no doubt for me then that my money is going where it is most needed.