I have not used the XT-50 and it is highly doubtful I will ever give one a try but here is what you might see when comparing it to the XL Pro.
Depth.. maybe deeper than the Whites but you will be digging lots of bouncing numbers to get the deeper stuff. Throw that good solid ID you are used to out the window. You could probably do just as well by paying attention to the audio on the XL Pro, going by that rather any VDI reading.
The only things I can see to justify the 50 over the XL Pro would be its ability to be swept slower with better seperation in trash. Of course you will have to wait for ML to come out with a smaller coil to really take advantage of that. The posters are saying that the 9" coil does good for its size in trash, but I wonder just how many of the targets they are getting would not have been seen by the "moderate" sweep of the XL Pro using the 8" coil?
NO timetable has been set for additional coils at the lower frequency. Other than the obvious differences of tone ID, accept/reject settings ect.,I think that about covers it.
I hope Monte weighs in here as I would like to hears his thoughts on what he has seen so far comparing these two models.
Tom