You could gain some "flexibility" if you had the X-70, compared to the X-50. But honestly, unless you are desperately wanting the 3 kHz coil or a Prospecting mode, you can do just about everything with the X-50 as you can the X-70. Just not automatically. On the other hand, I've had both the XLT and the M6. In my opinion, there is no comparison between the two. Not for a guy like me, that hunts old sites for old coins. Most importantly to me, the XLT (and X-Terras) offer notches opposed to variable discrimination with the M6. Reject too much and you'll miss some valuable coins and jewelry. If you are comfortable with the functionality of notches and are able to tweak the XLT accordingly (AC Sensitivity, DC Sensitivity, Mixed mode, Trac speed and offset), hang on to the XLT. At 6.59 kHz, it is a better coin finder than the M6 at 14 kHz. One other consideration would be to wait until the "jury" reports on the new White's 6T. At 8 kHz, it only has two PZ coil options. But if White's has more success with this line, they are probably going to make more coil choices. Unfortunately, it may be at the expense of the 6.59 kHz XLT. As you may know, the XLT is the only remaining White's model operating at that frequency. (gone are the 5900 series, 6000 series, XLPro, Quantum series, ID series and Classic III). And in my opinion, some of those "discontinued" White's models using that frequency are some of the best detectors around. Put that 350 Snooper on my XLPro and I can separate targets with the best of them! JMHO HH Randy