The 3030 isn't any deeper, you can find the same things with the E-Trac. If you aren't going into the water there are detectors that do coin hunting equally well if not better. The FBS machines are not good at recovering low conductors such as thin rings and chains while other VLF detectors will hit these hard. If you are going into the water, even wading, you don't want a detector that isn't waterproof, which the 3030 is - so that would be a game changer.
I've used the E-Trac for many years and the CTX - for fields, parks, schools, relic hunting, etc. I'd be inclined to go with a cheaper and lighter single freq detector for general purpose detecting. Unless you have mineralized soil that is limiting depth and TID there are many detectors that would do fine in relatively benign soil. In mineralized soils the FBS machines are deeper and have better TID at depth. But most detectors can TID to 6" or so ... with some accuracy, it is just that beyond that they tend to register non-ferrous as ferrous as the depth increases. That is the advantage of the FBS machine design, it can properly ID non-ferrous deeper, especially high conductor like silver coins. But, most people just hunt the easy shallower stuff and you can get by with an Ace 250 and still be productive. It is only when you start digging deep for the older coins that the FBS becomes more important to the detectorist, especially in mineralized soils.
I upgraded to the CTX because it is waterproof - the E-Trac worked just fine. But it is reassuring to know a sudden rainstorm is not going to damage your detector (I used to wrap the E-Trac screen in a clear baggie). I also detect now snorkeling and in the saltwater ... so in that case the E-Trac isn't even a possibility. Also, if you are determined to get either the CTX or E-Trac, the CTX is better balanced. The E-Trac's poor ergonomics will hurt your arm after several hours (I hunted for 8 hours with it many times but you had to switch hands occasionally to keep the arm from cramping up). The CTX feels much lighter, even though it isn't (so if you are going hunt for long periods the CTX will be more comfortable).
Again, if you don't need the specialized skills of an FBS machine or waterproof design, there are dozens of great machines that are very deep (deeper than the FBS machines in mild soil) and have better target sensitivity, and are much lighter and cheaper. The key is to do your research and avoid the hype (which is very thick when it comes to detectors). Most any detector in the $600 range (new) would work - more money doesn't mean more depth, just more add-ons and things you'll never use or need.
Lastly, I would recommend you buy used ... you can get that same $600 detector for half that ... most people are eternally on a quest for that magic detector. You can get a good deal ... just be sure the detector hasn't been damaged (by water or the owner). And just remember, if you don't like whatever you buy ... sell it (but give it a fair shake first). You aren't married to a detector. If you buy used and sell it a year later ... you won't lose much, if anything, and now you're just that much smarter about detectors and will probably make a better decision the next time you buy.
I hope you guys and gals can figure this out... Both are great detectors... Also there are a lot of fake CTX's out there. Be sue if you buy one you run the serial numbers through Minelab.. 
