Hi Paul, I am as you can see very late with this reply so it is probably no use to you now...but just in case anyway: I have both (as well as an 8x50 since this time yesterday!) and I'd say there is a definite difference. Not in image quality as both are superb but in ease of use. We are nitpicking here, as neither is difficult, but to me and some others I know the 7x42 is just straightforward easy: easy view of the whole image circle, greater brightness, generally very relaxed while remaining compact and comparatively light for the format. Another great 7x42 is the Carl Zeiss Victory 7x42 T*FL but that is now long discontinued and noticeably longer and bigger (AK prisms, which are very good for high transmission). By comparison the 8x32 also has an excellent image, possibly slightly contrastier, but repays careful readjusment of interpupillary distance depending on focusing distance and more experimenting with the eyecups for ideal setting.
In my case I love both and use the intended use as the deciding factor which to take out with me. Basically 7x42 for birding and more single-minded use; 8x32 for informal use, perhaps in company with a friend or two where viewing needs to be simple, convenient and perhaps not the primary task. But it could be these are not the reasons for choice but instead the post-purchase justification! Seriously though, if I had to decide on just two formats and models to keep, these would be the two. The 8x50 would be the third choice as it is just so good and surprisingly easy to manage despite the big eye, glamour bottle format! The smallest and cutest bin I have is the old 8x20 BCA armoured green Trinovid but it is also by far the fiddliest. After using that the 8x32 is ergonomic and viewing paradise!
If you see this post, I'd be very interested to hear what you did in the end and if it worked out to your satisfaction. It's easy to give advice but not so easy to know all the factors playing in someone else's decisions.
Tom