All of them have to be with BLD for me:
Having an easy scramble and fast memo and then...:
1. Making an execution error
2. Forgetting about the flipping flipped edge in DB (or just not seeing it)
3. Twisting a corner the wrong way
4. Forgetting corner memo (where corners are solved last)
Tbh, I agree with Artic here, I can't see how all of the 4 main methods can be exactly equal in speed or potential or whatever. Maybe the difference is so small, it isn't too noticeable, but I mean surely there MUST be some difference between the methods.
Don't be afraid to try and mod it yourself. It's not as hard as you think!
There are plenty of good tutorials on Florian mods on youtube, which I used to help me. Though saying this, I really ****ed up one of my Florian mods on the 4x4, I guess because I tried to rush it and overdid it. :/
I haven't read the other comments, but to me, it seems like you just need to practice and get used to Ortega.
You've only been using it a few days, and can't expect times to drop straight away.
Give it a few months of good practice and you'll be there I'm sure.
Leaning full-OLL will massively help. Especially considering your OLL is taking 5 seconds each solve! This can be gotten down to 2-3 quite easily, and maybe even lower with practice.
I've just been messing around on my cube, and it really isn't hard at all. It's basically like doing F2L twice as much. First a pair up the edge with the yellow corner. Then I pair up the white corner with the pair already formed, and insert. The only thing is, I can imagine it would be...