Spits are terrible trainers, in my opinion; all of them, mainly due to the fact that they maintain energy so well. The problem is how much they retain proportionally after hard maneuvering compared to other aircraft. Even a Spit V will maintain more E, proportionally, after hard maneuvering than an LA-7 will. This leads to a poor understanding of energy retention (mainly because few other planes retain E so well) as well as sloppy control of the aircraft. Flying Spitfires exclusively, especially for new pilots, results in learning tactics that really don't work in other aircraft.
I personally suggest the LA-7. It's fast enough that it'll allow you to escape and forgive you of over-handling, while at the same time possessing enough maneuverability to allow competitive angles.
Additionally, while the LA-7 is great at energy tactics and great at angles, it's not simultaneously good at both. You have to learn how to transition from one to the other, very much unlike the Spitfires, which have such great turning and climbing at low speeds that there's little distinction between the tactics. At the same time it's forgiving enough for a new pilot to learn. It's very balanced in that what you lose in angles, you pick up in airspeed, and vice-versa. It's an easy plane to learn the relationship between the two basic tactic categories.
Someone who learns on an LA-7 can transition to a lesser aircraft and, while the lesser aircraft may be harder to fly, most everything that was learned will apply. With Spitfires, the E retention is so high that the tactics make it very hard for a new player to transition to another aircraft.
I'd urge against the P-47 and the P-51. Both aircraft lack acceleration (with the exception of the M with WEP) and will get you in the habit of fighting downhill. Until you've mastered the basics, this will only develop bad habits. Additionally, while the 47 can be rather competitive with a good pilot, the 51 isn't nearly in the same category. It's good for BnZ and hit-and-run tactics, but the only great thing about it is it's speed. It's a jack of all trades and a master of none, and it's the last plane a new pilot should be flying, IMO.
My suggestion for new pilots would be the LA-7 (as mentioned above). If you're against low ENY aircraft, then try the Yak-9U. Once you feel you've mastered those aircraft, then switch to something like an F4U-1a or P-47M.
