Last night three of us from the corp decided to give a level 5 mission a try.
We went in with a Tempest and Raven battleships, myself in a Nighthawk, and my alt Derranna in a Scimitar logistics ship. The mission was called "The Fortress" and for good reason.
The inital spawn had 6 heavy neutralizing towers and a ton of Republic battleships, battlecruisers, cruisers, and frigates. Of course, everything aggro'd me. My cap was gone immediately and my shields shook under the fusilade, but with the two large shield transporters from Derranna's trusty medic ship I was able to withstand the barrage. Barely.
With the initial wave destroyed (after a good thirty minutes of fighting) we targeted the objective building, a Capital Ship Maintence Array. The reported intelligence was that a wave would spawn upon getting through shields, another for getting through armour, and a third for getting into hull. We got through the shields quickly and the order went out to cease fire as the Republic fighters spawned... but my salvos already en route didn't get the message and slammed one after another into the objective, triggering the second spawn of battleships and cruisers.
My Nighthawk was obliterated. To be accurate, I saw the shields fall to 50% DAMN FAST and hit warp button, but I think I might have warped to wrong object (i.e. wasn't aligned to it, I was aligned to something else) and I didn't make it out before the ship exploded. Almost, but not quite.
Ah well, crap happens.
We regrouped and discussed what to do. I had my Basilisk in system so we decided to try to warp the Raven in at 100 km range, and then have the two logisitics come in and rep its shields like the devil. Our first attempt didn't work, the Raven had to warp... but we got a better bookmark and second time in we had enough range to avoid a lot of DPS from the sentry towers and the four large shield transporters, 10 shield drones, and 2 large energy transfers proved sufficient to maintain the Raven's tank and cap.
The third wave proved easy to handle after that wild ride and we collected a cool 23K loyalty points each for the effort. If you are looking to build up Loyalty points, level 5s could be a good option.