[Edit: as has been kindly pointed out, there is no "version II" as such. What I'm referring to in the title is the 100mm f/2.8 L IS USM Macro versus its non-L non-IS predecessor].
I already have the 100mm f/2.8 macro and have always found it difficult to obtain sharp hand held images. I'll be travelling soon and I'm wondering if it would be worth upgrading to the 100mm f/2.8L II IS, particularly as I probably won't be lugging a tripod everywhere with me and in any event as I'll be with my family I probably won't have the time to think too much when macro photo opportunities arise, least of all set up a tripod.
Does anyone have direct hands on experience with both lenses and if so, I'll be grateful for some feedback on how they both perform in the field and whether the upgrade is worth the additional cost.
Also, I'm wondering if 100mm is sufficient for 1:1 images of nervous flighty things e.g. flies, dragonflies etc or whether a longer focal length lens would be better. Having said that though, the 180mm macro costs twice as much and also doesn't have image stabilisation - coupled with the longer focal length, I should think that would make it even more difficult to hand hold?
I'm erring towards investing in the 100mm f/2.8L II IS, but what do you think?