I have been detecting for about 20 years now. I think that many folks would be perfectly happy with the Delta. I own one and use it a lot. Here are some advantages; very very light, one 9 volt lasts for like 40 hours, 99 target ID numbers, able to use 1/4" AND 1/8" headphones, dd coil is available, all metal mode, best pinpointing machine I have used. I detect in New England and some times the numbers do jump around. Here's my process. I swing at my normal pace. If I hear a high tone, I slow way up to investigate. If the number are jumping wildly around you pretty much know it's just. I find that the numbers stick dead on IF you are directly over the coin. I was out the other day and trust mve, you can tell a coin, just slow down and listen. Quarters, dimes and pennies (the older ones) sound off with a high tone. Pinpointing is brilliant, tells you the depth and goes louder as you get closer. I looked very closely at the ace 250, but I think that this detector is far more user friendly. First, it gives you actual target numbers that I prefer. The numbers are large and easy to read. I also like that you can you it in all metal and still have target is numbers too. Only negative aspect in my opinion is that this unit will either detect an object or go silent. My old Fisher 1265X would get softer as the target went deeper. I have no complaints since there is a depth meter both when doing a general search and during pinpointing.
Hope this helps out a bit.
Bobby