If you are looking for something with which you will never have an accident, get the p-style. It is not a packer, just a urinary device, but it works every time with no worries and no skill involved. The only problem is that it is not easy to conceal because it is hard plastic. It is very inexpensive! I think I bought 2 of them for $20 and am still using them 5 years later. The clear color is the least noticeable.
If you want a realistic phallus type device, the EZP would fit the bill, if you have a couple hundred dollars to spend. I was a little disappointed in mine. Yes, it is realistic, and can be used as a packer, but it is hollow, of course, and just smashes flat in my pants, making it look like a little weird. I would say it is not a great packer, but an okay urinary device. I have had a few accidents with it, however, so it is not as fool-proof as the p-style. I had higher hopes for it, especially for the price. I pictured myself using it at a urinal, but I don't think I trust it fully like I do the p-style.
Having tried many other STPs, including making my own, I have found the best solution for me is to pack with my regular packer and carry a p-style with me if I will be out and about using a public restroom.