It depends on what you are doing with it. If you are racing, you should go radial. If you are cruising and plan on using your furler to reef, go with cross cut.
No genoa will furl flat after more than 20% or so, unless you had one cut flat for that purpose, in which case it would make a lousy sail when not furled...
These two comments really get to the heart of the issue - A couple of sailmakers, most notably Mack, claim that on a miter cut sail, as the material stretches, the draft remains further forward and the back of the sail remains flatter. This helps to retain the shape, even as the sail is rolled.
I am currently sailing with a 140% genoa that I got with the boat. It has horrible shape to start with and (obviously) only gets worse as it is furled. It is a handful in strong winds with lots of weather helm and spends a fair amount of time partly furled to reduce the overlap. I am going to go down to a 125 or 130 which means it will spend less time part furled and, being a new sail should have much better shape overall. But keeping the best possible shape when part furled is still appealing.
Just to make things more complicated, I just read that Crusader Sails (well respected in England) recommend a bi-radial, as opposed to the usual tri-radial, for furling applications when the furler is used to reef.
Cross cut is cheaper but losses shape more quickly than the more expensive radial cut.
With cheaper dacron this is undoubtedly true but Hyde, for example, claims that cross cut in Marblehead retains it's shape better than tri-radial in Warpdrive. Tri radial starts out better but deteriated more quickly. Also comparing prices, again using Hyde as the comparison, there isn't that much difference
Crosscut Marblehead HA 9.77 9.1oz $3771
Tri-Radial Warp Drive Cruise 9.11 9.1oz $4274
I am looking at the more expensive sailcloths in the expectation (hope?) that it will retain a decent shape longer. Maybe I should just go cheap with the expectation that it will need replacing sooner. For further comparison
Crosscut Dimension Polyant 9.1oz $2657
CDX Cruise laminate $4281
Just to muddy the waters even more, Challenge have a new sailcloth, Newport Pro Radial, which uses the same 104 fiber as Marblehead. To quote, " Sailors who are looking for a performance upgrade from a crosscut sail, but still want the durability of a high quality woven will excel with Newport PR
. The combination of technology in this line provides a strong alternative to a very expensive Warp-Drive Sail or a Cruising Laminate Sail".
Initially I thought I'd have to choose between tri-radial or crosscut and then pick a loft. But now I have to decide between Tri-radial, bi-radial, miter-cut and crosscut. Multiple sailcloths and not all loft offer all options. Maybe I should just convert to Junk Rig or buy a stink pot.