I had also bided on the Tower Mint set at the same time (just in case I didn't win the Coincraft set), forgot that I did and after winning the Coincraft set noticed I was still the highest (and only bidder) on the Tower Mint set & ended up with both sets.
There are slight differences between the two sets:




First off, as you can see the Coincraft set has a more detailed background that actually look like images of real flags taken in motion, the Tower Mint set is all print/hand drawn images.
Next off comparison of the two sets, due to my cheap scanner (it was only £60 out of Argos) certain areas of the image are a bit blurred, so I thought it best to show comparisons with the largest coin, the 5 ECU
Obverse

Left: Tower Mint, Right: Coincraft
There are a couple of differences, the first most obivous are the sun rays that are fully present on the Tower Mint coin but not on the Coincraft one, there are rays on the Coincraft one but there are alot less of them. Secondly the arms of Neptune and Europa are in a different place on each coin & there is less detail on the body of both Neptune & Europa on the Coincraft set.
Reverse


Left: Tower Mint, Right: Coincraft
Again there are some differences but on the reverse at least they are very simular, one thing that is missing are the harp strings on the Coincraft version & also there is less body detail on the Coincraft versions again
Apologies for the picture quality again but this is due to my scanner