I had a classic 3 SL since 2000 and just bought a teknetics delta 4000 myself .Tell you the truth I think the whites is a better machine I'm not really impressed with the the delta I think I'm gonna sell it. It is a very light machine and has a lot of features but I like the beep and dig better. Anyway I hope your daughter likes it.
Honestly for my daughter to just follow me around digging either would have probably worked good, she just wanted something lighter. I hadn’t thought about getting a dd coil for the d4000. I have dd’s on my mxt all pro and at pro so why not on hers as well.