It really is very hit or miss with a lot of these, as has been mentioned. Some, like Golbat, Murkrow and Doduo, sound much more natural than they did, which is very nice.
Others, such as Drifblim and Garbodor, just don't sound right any more. Drifblim's cry sounds more like some kind of dubstep song than anything, and Garbodor sound like it's on the other side of a door or something (And it lost the weird fart noise that it had at the end, which is a shame). There are many more that didn't need changing and now have worse cries than before.
What I find strange, however, is the fact that while the likes of Drifblim and Garbodor, whose cries were fine as they were, have now received updated cries, several others, like Lapras and Rhyhorn, don't seem to have changed at all, despite the fact that their cries are much choppier due to them being very old. I want to know what the reasoning behind that choice was, because to me it makes absolutely no sense to fix what isn't broken and then ignore the things that actually need fixing.