Great question! I'm a dedicated swimbait fisherman so know what you're looking for. After having researched and handled the "D" series extensively, I wouldn't buy the "D" series. They're difficult to set up and maintain without having to remove the covers on the reel and the reel doesn't have thumb screws like the previous TE series did so it's a reel pain in the keester having to do it with tools especially while you're trying to set your drag!!! The screws are on the handle side and the entire case covering the spool to the left side comes off when the screws are removed! Alot of folks complained about it when it was introduced.
I have a some Luna's (300) and several TE's (400), they are really great reels for hard use. Knowing what I know about the Luna and TE series and having used them extensively for some time, I'd have to say let your pocket book decide, yeah they're both that good. For the money, I'd recommend the Luna 300 @ around $280 as your best buy. Though you might also want to consider the new Conquests which are also exceptional, expensive and a notch up from the previous TE's. A sleeper I own and can recommend if you can find a used one, is the disco'd Daiwa Pluton, which are tough as nails and then some.
A reel you didn't ask about that I would strongly sugg
est is the new Daiwa JDM Ryoga Shrapnel Japan limited from http://japantackle.com/ which replaced the older, previously disco'd, limited edition, "snakehead" fishing reel, the Daiwa Millionaire Black Sheep, which was probably the best built level wind on the planet for the money so this new model should be at least as good and then some.
Hope this has helped some ... let me know if you have any other questions about these reels I can help you with.