What format do you intend to battle in? Fastgun - MWC or IRCWCC , Treaty or BigGun? How do you envision your style of battling? I captain a fast-gun Derf under IRCWCC rules. I run 4 guns and a half-unit pump - I wouldn't recommend this setup to a rookie. In MWC I believe the Derf is forced to run 3 guns and a full unit pump, which is more rookie friendly (mistakes aren't as punishing) but provides less offensive firepower. The Derf is fast, accelerates well and has reasonable turning ability for its length and rudder configuration (two inline). It plays very well as a hit and run ship. It is less well suited to hug and slug, though it does have very little freeboard which gives it an advantage over later ships if you can get in tight. She is capable of being outfitted with a small armor belt fore and after which can really cut down on the damage you take in the bow area. Driven in reverse Derfflingers have a tendency to submerge, a condition that plagues many ships from this era, so you will need to learn quickly to seal your decks well (and in my case plug the openings in the D turret). My Derf! is a Strike hull, but doesn't use their new nifty deck kits or superstructures. If you opt to go with the Derf I would suggest getting those from Strike as they make things much simpler and you will be on the water faster. Derf! Derf
It can be a good rookie for the reasons noted above. You can also make the gun set up twin sterns and a haymaker. Without the bow sidemount you take less damage.
In our local game the bow sidemount is great for overtaking a convoy ship. Or turning inside of the Richeliue and sitting nicely behind his nasty dual sidemounts where he can't shoot me. Definitely a situational gun.
Don't know what format I'm going to play in. Going to move to lower Michigan soon, so what ever is around.
I built a Derf as my first boat. I think she is one of the prettier boats out there (that may or may not matter to you). With 3 guns she is a fairly easy build that is best battled more like a cruiser that can use sidemounts. Play sidemount games with the little boats and you will pay for it. For MWC she would be a good rookie boat. If you like the idea of staying on the edge of the furball then she is a blast to run, but if you want to charge straight in to the fray then there are better boats out there.