It is definitely a favorite for me for a lot of my hunting needs. For the month of September I left it on my Omega the entire time. A full month with the 5" Double-D confirmed for me just how good it is. i have always preferred a smaller-than-stock coil for a bulk of my hunting due to trash and/or tight confines in homesteads, ghost towns, or in the brushy areas that have grown on the fringes of old parks and such.
With other things going on and doctor visits it cut in a bit on my time but that dinky coil still helped pull 895 coins for me in September, several sterling silver jewelry items and a gold bracelet and 14k gold ring. Whether using the stock 8" or the 5' on your Delta, you still need to make sure you learn the best sweep speed for success with each of them. The Delta works different from the Gamma and Omega because it has a different audio process. With my Omega i can get a little better weaker-signal depth due to the 'gray scale' or 'proportional' audio response where as the Delta relies on a 'saturated' or 'binary' type audio report. In short, if the Delta gets sufficient signal to process, it is sent along with the 'saturated' or full-strength audio report to its functional depth.
It's nice to have a variety of detectors available to us and I personally like the compliment of the easy-to-use Delta to make a good 2 or 3 detector arsenal. I just finished two days of seminars for a local dealer this weekend and used a variety of detector sin the classroom session and then showed what they could do in the park setting. It was easy for folks to see why I like the delta as my quick-to-action unit. I've been using all of the Teknetics coils on the delta, Omega and G2 this last few days in some comparisons afield and, as I found in August, the 5" DD did well. Just know that because these detectors process signals a little differently you want to make sure you know the best sweep speed for top results with them.
I live in NW Oregon and we don't have much mellow ground here. Plus there's a lot of 1, 2 and 3 bar readings on the Omega's Fe3O4 display so we have some challenges, but the Delta does quite well. Let us know how that 5" performance works after several times out. I think you'll like it a lot. I know i do!
Monte