No, not a performance comparison, just a discussion on how the two can share a race-course together safely, without incident.
I`ll address a few issues. Feel free to disagree or contribute, let`s keep it nice & friendly. I started this discussion in another thread but in the context of that thread it got a bit out of hand.

When a spin-boat goes downwind he sails deeper than a non-spin boat. Both are sailing their "proper course", but their courses are converging, assuming the spin. boat started higher than the non-spin boat. This does occur through a number of situations and is impossible to avoid all the time. (A non-spin boat gybes at the mark, then gybes back 50m later, he has put himself to leeward of a spin. boat who rounds the mark after him. They are both on starboard.) In this instance the spinnaker boat is the weather boat and MUST KEEP CLEAR, under the current rules.
(I am not lobbying to have rules changed, just looking at the options.) Having said this I believe the current rule assumes that both boats are carrying spinnakers, or not.
The rule is also written to allow the leeward boat to protect his source of wind, essentially it is a performance-based rule first, and a safety-based rule last, and is biased toward racing situations (in cruising it would not matter much which yacht has right of way, as long as it`s one of them, and everyone is clear on which one !).
Another factor to consider when sailing with a spinnaker is that if you`re hit by a big gust, your only safe course of action is to bear off to prevent a capsize. Now, I`d rather capsize than hit another boat, but what if you are close to other boats and might capsize onto another boat ? This might occur if you saw the other competitor gybe away onto port, and missed seeing him gybe back onto starboard 50m below you, as you were hoisting the kite at this moment.
Another thing to consider is the issue of blind spots. On all boats they exist, and people do have accidents because they failed to see the other competitor. In fact I`d imagine a large pecentage of accidents start this way, and they only see eachother when the right-of-way skipper has all but lost his voice from hailing. At the speed we sometimes travel you don`t hear a call until it may be too late.
Ok, let`s look at the blind spots.

The images show your blindspots in 3 different situations : Single-handed trapezing, single-handed sitting, and double-handed. All assume you have a window in the mainsail. Now, depending on the angle of heel, the window might be showing you the water rushing by to leeward, and nothing else.

So, assuming the rules are not going to change until we`re all old & sailing hydrofoil boats at 50 knots boatspeed, what`s the best way to avoid this (other than not using the spinnaker ).
Please, no comments on how only a "poor skipper" would ever get into this situation, only a non-racing sailor would have this outlook.

Cheers
Steve