Pros:
Display: Arguably the best smartphone display to date, a Quad HD (QHD) display with over 577 pixels per inch (PPI), the contents on the screen really jump out at you. The Super Amoled screens patented by Samsung have only gotten better with each iteration of their phones. You have the choice to make the display super saturated and make colors really pop, or dull it down to a more true to life look with the display mode Samsung has implemented into the software.
Camera: Again arguably the best smartphone camera to date. Using Sony's IMX240 sensor along with a new f/1.9 aperture lens with Optical Image Stabilization (OIS) really helps the S6 and S6 edge outshoot the competition when it comes to low-light shots and camera altogether. The phone also records in 4K, the front facing camera is bumped up to a 5mp camera with real time HDR. Samsung has done a wonderful job with the settings and user interface for the camera, really simplified things making it the best choice to go with for a really great camera with not much effort to take great pictures. There is even a "pro mode" that lets you really dive into the settings and manually set things such as iso, aperture, and other settings to get the right picture.
Performance: This thing is stupid fast and powerful, Samsung used their own in house processor for the phone, the Exynos 7420 which is an industry first octa-core processor built on 14nm technology. Essentially it uses significantly less power (about 35%) less than other competing smartphones that use Qualcomm's Snapdragon processors. Another industry first is the 3gb of LPDDR4 ram samsung uses, all you really need to know is that it's fast!! The addition of the new finger print scanner on the home button is a much needed upgrade from the Note 4's and S5's. Similar to Touch ID on the iphone.
Internal memory: Now this one is sure to throw a lot of people of, how can internal memory only be a pro? Let me explain the reasoning behind this. In the past, Google allowed users to install or move some of their apps to their SD card, a lot of people took advantage of this option, however and here is the problem with this, most users don't understand that internal memory is and will always be faster than an external source in this case the micro sd card. By moving apps, games, pictures, videos to the micro sd card, the card has to first read and scan the card for each file before loading or opening anything, and the speeds all vary depending on what type or class sd card you have. Were you cheap and kept the same sd card you had from an older phone that was as old and slow as dial up? Or did you opt to purchase the newest and fastest and definitely more expensive class 10 and higher sd card with read and writes speeds in the 80/90 Mbs? Most likely, you didn't want to spend $50-100 on a new sd card and ultimately suffered slow speeds, poor performance that didn't live up to expectations on a new phone and think how can this be? Now back to the internal memory on the S6 and S6 edge. Samsung is using an industry first Universal Flash Storage (UFS 2.0) memory in the phone that takes advantage of speeds much much greater than anything on the market right now. I like to make the comparison between SSD vs HDD. If you have a new laptop or upgraded your desktop to a Solid State Drive, you know the difference is literally night and day. Before it took you several minutes to boot up your computer, let it display the logging into windows animation, then after you log in to your account it takes another 2-3 minutes before you can even open or touch anything without your computer freaking out and freezing. Now with SSD, the computer is up and running, you're logged in and you can open 20 different applications and programs all in about 30 seconds. That is the difference between SSD and HDD on computers, and it's kind of the same thing with the UFS 2.0 memory samsung uses for the S6 and S6 edge.
Charging: Quick charge on the S6 and S6 edge is extremely fast. Most times, I can fully charge my phone from dead to 100% in just a little over an hour. The S6 and S6 edge have the fastest charging battery on the market. The built in wireless charging is also very convenient when I just want to lay my phone down on the table beside me at night without having to search for a cable and plugging it in in the dark.
Six Appeal: Last but not least. The phone is simply sixy.. See what I did there? The Edge is a looker, it will attract all kinds of attention, random people will stop you and ask is that the edge? Simply put, it's a gorgeous phone with a really nice feel of premium material.
Cons: Battery life isn't great, it isn't terrible by any means, it's just not a phone that you can go 2 days or even a full 24 hours with without having to charge. On a normal day, I wake up at 9am. check emails from several different accounts, exchange servers, facebook messages, notifications, text messages etc etc. by noon and after lunch time and having watched 30-45 minutes worth of netflix, I'm down to about 75%. Throughout the day of a couple hours of phone calls, constant emails syncing, paired up to my Moto 360 smartwatch, having another bluetooth earpiece paired up, streaming some music, using gps on the commute home, i'm down to about 40% by around 6pm. By the time I'm going to bed at midnight or 1am. I'm down to about 20%. Although it is nice to know that I can use ultra power saving mode if need be, and that with only a 10 minute charge, I can get 4 hours of usage from the phone. If I come home at 6 pm and have only 40% battery and I'm going out in 30 minutes, I just throw my phone on the charger for 20 minutes while I get ready and I'm already up to like 80% in that short period of time. Guys, I'm a power user, I use on average 30 GB a month of data, over 10,000 text messages, and over 6 hours of talking a day. If I can use this phone to the max without any complaints than so can any non heavy users.