I have experienced both communities.
I love Emerald Island for its feeling of space and grandure (especially in the Enclave section). It is a larger resort than Windsor Palms. If you plan to spend time at the clubhouse you may find yourself driving if you don't like to walk far. EI has the tiki bar but the rest of the amenities are not on a par with WP.
Windsor Palms is a smaller community and overall has better community facilities. You can probably walk from any home on WP to the clubhouse area. It does not have a tiki bar but does have a great community store. I also know the owner of the WP home and he is very active on the HOA there.
As far as distances go, WP is a little further out, but it makes only a couple of minutes difference in driving times.
Both are great communities, with different feelings. If you were going to spend more time at 'home' then I would recommend WP over EI due to the better amenties. However, if amenities are not an issue, then I would go with the home that worked better for my needs.
Things I would consider:
pool aspect
owner response (prompt, courteous, well written etc)
how well the home meets my needs (bedding, pool. spa, other amenities such as wi-fi etc)
Hope that helps,
--Kay