They are basically the same and should perform about the same. If forced to choose and you are installing this on a roof then I would probably go with the second one only because the vacuum release valve is on the shortest piece of supply pipe. It will close a bit quicker and will allow you to run at slightly lower pump speeds (i.e. lower pressure) if you have a variable speed pump. But even then it will be a very small difference.
Note too, that the return pipe could come back over the top if that is more convienent. Just don't have a local high spot or it might not full drain.
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