What an amusing thread. Seems like the question originally asked in the subject line was diverted quite quickly and we return to the partisan politics of metal detecting! Was the original question in the subject line really what the original poster wanted answered, or was it a setup to stir folks up?
Naturally, newer machines will find modern coins, gold and relics as well as older coins. They are after all,
metal detectors... they will all detect metal!
A lot depends on what you want to find. I know many XLT and DFX users and some are ring hunters, others relic hunters or coinshooters. Those particular newer machines work for
all these types of detecting.
As far as the old Compass machines, etc... if you have one, great! But most of us cannot just go to our detector dealer and get a 30 year old Compass, or any of the other detectors no longer manufactured. We are stuck buying newer machines, so discussing the merits of older machines is really not practical, no matter how good they are or were in their day.
Relic hunter, Civil War hunter, Coinshooter, Ringfinder, Water hunter, Prospector... different strokes for different folks. I may be a coinshooter, but I respect my fellow detector users who seek other treasures. I hope that you can be as happy with your finds as I am with mine. Let's respect our fellow detectorists and their style of hunting, rather than belittling or mocking their chosen pursuit. (Some of us get tired of those boastful "colonial only" posts too, you know?
)
Another thing to consider is where you are detecting and the type of digging you can do. In manicured parks and home yards, I'd be hard pressed to "dig all" or even "dig many" - so cherrypicking is a necessary evil. I do my best to choose my signals. A newer machine gives me more data to make an educated guess as what to dig. Estimated depth is one of the most important pieces of information my newer machine gives me, but the suggested ID information is also valuable. If I were digging a pasture, field or woods where digging didn't matter I would take a chance on almost all non-iron signals. So, it's not just preference, it's the limitations on my activity imposed by the sites I have access to. As dirtscratcher said, "...you hunt what you got."
More of the discussion seems to have focused on cherrypicking, rather than detector choices. If someone can buy a new machine and go out and dig a handful of coins their first time out they are much more likely to stay interested in the hobby than if they have to struggle and fight the machine to know what it is trying to tell them. Also, I'd rather have a newbie with no training and their mail order detector
not digging every target at the park and leaving it a mess of diggings and dead plugs everywhere. I think most detector users as time goes by, reduce the discrimination they use, but for beginners, discrimination is a great way to learn.
If you're tired of hearing about one brand of machine and one type of detecting, start posting your own finds! Instead of perpetuating the empty arguments let's hear about the relics, rings and nuggets you're finding with your machine of choice. Saying your machine is best and makes the best finds is all well and good, but
seeing is what convinces me. I chose my particular detector because I saw, in person and online, people using that machine making the types of finds I wanted to be making. I did not see the results I wanted as overwhelmingly with other brands or models - the other brands and models seemed to be more-or-less like my older machine. So, I purchased that newer detector and learned to use it well and guess what... I'm getting the kind of results I want.
I also noticed that the people who chose the machine I use tended to be more "hardcore" - they were detecting a lot. Not just a Saturday afternoon once or twice a month. These guys were out 10, 20, 30 hours a week and doing lots of research. They knew the history of almost any ground they waved their detector over. The research you do and the time you spend detecting are important too. Any detector will make great finds on a good site that has not been detected before. For example, squeaking one more keeper out of a well detected park that doesn't even have pulltab signals left in it is another story. Sometimes a different brand, model or searchcoil (paired with experience) can make the difference in getting a tired site to produce.
I started with a two knob, no meter machine many years ago and made great finds, and dug a lot of trash along the way but I hope I'll never have to go back to using that old technology again! With my new machine I am digging MORE keepers and LESS trash. I could dig more trash, but why would I want to? It's not my goal to clear out all the metal in the ground or to make a profit, but to end up having a fun day finding goodies. With my new machine I am finding more treasure in my pouch at the end of the day.
I guess something of an alternate answer to the original question is, newer machines are good for finding all the targets older machines could find
AND are better at finding older coins, especially in hunted-out sites.
As far as iffy signals, I dig plenty. I have flat buttons, square nails and antique toys as well as gold jewelry and other relics that I treasure. So I am even cherrypicking the iffy signals, if that makes sense. The other advantage of my newer machine is that the signals that were iffy on my old machine are now solid. The new machine is better at target ID than my older machine, so there are less iffy signals to dig. The newer machine gives FEWER iffy signals than the old machine. Nowhere near the iron falsing I used to get with my old machine. So, I am digging fewer iffy signals because the ID is more accurate - there are less iffy signals to dig! Do I know this for sure? Sure, because I keep digging random stuff and iffy signals at times to make sure, and darned if that newer machine is really accurate.
Joe......you have the most unique writing style......lots of ellipsis......no other punctuation and the occasional.......ALL CAPS.
They always seem amazed that I am still finding silver there and say that they haven't found silver there in many years, while they defend their fabulous 20 and 30 year old machines. 
