When you think about it, Shrike is just a Vigilance with point defence. In general, I find it below the trio, but not necessarily bad. The only issue is that without a heavy blaster it desperately needs missiles or support, which means it's either a limited use ship or an escort.
It’s really not. The vigilance doesn’t have the cap or shields or maneuverability to fight ships straight up. It’s a harassment missile ship where the main gun should be used for rangefinding. It can be used as an assault ship but it doesn’t have the punch to be terribly effective because the only really good medium energy weapons against armor and hull are the HB and phase Lance. And it does not have the cap to run either even in bursts.
The Shrike is an assault ship. Able to quickly kill soft and semi-hard targets with ease. Against frigates it simply overpowers them with superior cap and dissipation. Against destroyers and above it can volley shields with missiles.
If you had prior played with a Medusa as an SO player main destroyer then the Shrike is probably a better option. The Medusa doesn’t have the cap to consistently run 2 HB and doesn’t have the slots to fit strong strike missiles like the Shrike does. Plus it can be hard to find 2HB (sabot pods are more common) which means that pre-colony production the Shrike is almost twice as replaceable. Sure, the Shrike only has one HB. But because it replaces the second with a zero cap weapon it got a lot more effective flux dissipation and when SO’d probably doesn’t even need full dissipation. (Which lets you balance how much secondary weapons/PD you decide to fit).
The Shrike is also 25% DP cheaper than the Medusa