This depends on the actual melees and their current situations. For some (DNC, THF, and NIN) it's possible to cap total delay reduction with haste alone. In those situatiations, yes, attack songs. The general rule of thumb, though is this: If marches have an effect, use marches.
In the most common TP set ups ninja does not cap total delay without songs. With af3 head, af1 body, and suppa even with full gear and spell haste they are not capped. They get full benefit from march2 and only need to change one piece of DW gear out when receiving both songs. Generally they will use af3 body in these cases. And even in that case marchx2 will give more damage than march/min even though they aren't reaping the full benefit of the second march.
Thief gets even fewer DW traits. They aren't capping without march.
Dancer can, but then again they are never used now in voidwatch or abyssea (unless solo then no need to discuss it).
March is just infinitely better.
Edit: put more plainly, with 50% DW (35 traits/suppa/af body/af3 head) you can still use 60% haste without hitting the cap. 25 from gear. 15 from spell. 15 from march 2. That still leaves you 5 to benefit from with march 1 and that will give you more damage than minuet because of the increasing awesomeness of haste at high levels. With those buffs active take off af1 body and put on af3 or juogi, but don't change songs. Edited, Aug 30th 2011 7:44pm by BarberofSeville