As the NR I like to use MC90/80 as the backbone of my fleets. They always take point and cover my carriers in the back since spamming fighters is what the NR does best. I do like the Nebulon SD and the Bothan Assault Ship in later eras to take point with the MC90s.
I've probably fought against the later-era New Republic more than I've played them, but those Bothan cruisers are bastards. Attacking a NR fleet with a few of them in it can get a bit nasty when them and the K-wings decide to start focusing fire on my ships.