Well I have had my Samsung Galaxy S6 Edge+ for about 5 days now. I sold my iPhone 5s early, and also use the iPhone 6 Plus fairly often. For the test drive, I transferred all my data and my sim card to the Edge, and carried this as my sole phone.
First impressions were excellent. The phone looks sharp and the screen is (to me) far superior to the iPhone. The phone also feels far better to hold than the iPhone 6 Plus. I thought the Edge was smaller, but when comparing them they are almost exactly the same size. Despite this, the Edge just seems much easier to use one handed.
Transferring all my data worked decently well, but required me to plug my iPhone into my iMac and decrypt my information. The transfer program also crashed every time my phone's screen turned off, requiring me to change the settings so my screen was constantly on before I could successfully transfer data from my iPhone.
The back button and app change button are nice, but I find myself hitting them fairly often without meaning to. It does generally make it easier to change apps though.
Unfortunately there are many quirks that have made the Edge very annoying to use. The ads on the home screen, and especially the whole page of Amazon advertising I have to swipe through is just horrible when you pay so much for a phone. As others have mentioned, the screen is also not as sensitive and there are many times I have had to tap something several times.
There are other little quirks, but the worst part to me is the horrible battery life. The battery discharges very fast. After giving it a few days, I tried to use the phone for the full day. Got up around 7am, and by 5:30pm the phone was down to 5% and essentially unusable.
I do like the phone overall, but the many little annoying bugs, the advertising even on the home screen, and poor battery life mean I will definitely be staying with the iPhone for the next couple years.