The Serapis.... It just can't take a hit, and without adjusting my stick's sensitivity, it's too nimble. I like nimble fighters, and I like the don't-get-hit design philosophy of interceptors, but the Serapis takes it all to too great an extreme. The loadout options are great, but if you don't survive long enough to deliver your ordinance, it doesn't really make a lick of difference.
Next to that, I've a minor gripe with the Myrmidon. I just don't get the two half-sized secondary banks. I know it allows for more variety, but I can't think of the last time I actually put three different secondary weapon systems onto the ship. I also tend to get frustrated shooting down Myrmidons (and Taurvis for that matter) due to the design of the back end. I've a bad habit of slightly under-leading my target, so once a Myrmidon's shields drop, most of my shots pass around/between the prongs protruding from the ship's stern.
Still, I'll fly a Myrmidon, even when given other options. The Serapis? Nope. I'll fly intercept in a bomber, before selecting a Serapis.