TBH in terms of full features, GoSMS is still tops. It's full of customization including LED control, vibration length, popup customization, repeat reminders, group MMS, blacklist capabilities, private box, backup, blah blah blah. It's got search capabilities by message AND contact, which is huge.
The big downside is it's spammy and it's bloated.
Textra - Good features, but could be more #HoloYolo
8SMS - Just like the CyanogenMod SMS/MMS app which is based on AOSP. However, AOSP is somehow very slow. Just scroll through a list of 50 text messages. Look how slow that scrolls compared to say a huge list of Gmails.
Evolve/Sliding Messenger - These kids are in college, and it's cool they're so talented, but in many ways this is more a hobby/side project than something professional. They still can't address the fact that their app load so slow and can't handle large amounts of messages when most other apps can do just fine. Evolve seems to be better, but what's to prevent these guys from doing another reboot and you throw your money away again?
Hello SMS - Seems to be the best new app right now, but they need some more features.
Something that most apps lack - Searching SMS would be critical. I hate trying to find an 8 month old SMS conversation with a friend. Instead I end up typing their name to start a new thread and to see what old messages there were. It also makes it hard when some people have 2+ numbers, and I forget which one is their text #. It would be helpful to have a search by contact, and GoSMS seems to accomplish this nicely.