I would use the Aestrom all the time because of its firing arc, if it would be able to use Artefacts, instead I use a Megaron because of its good PTA firing arc and just general balance, plus it can use Artefacts.
For Cruisers I would have to choose the Garid because of its speed and looks.
For shuttles I use MK1 because of its fast Hyperdrive recharge rate and cargo capacity.