I recently passed the FRM level I in november and i used the Schweser material after two failed attempts using Bionic Turtle.
So after trying both i can say that i feel more comfortable using Schweser. BT’s material is VERY short and i always felt that i needed extra research to fully understand concepts because BT assume that you have a strong financial background. What used to frustrate me with BT is that i read the notes and i feel that i have understood them however once i go for the practice questions it’s like i absolutely have no clue about them.
I came to the conclusion later on that BT actually explains only half of the chapter in the notes and the other half is explained thru their practice questions which was really frustrating for someone who has almost no finance background and who actually used to hate finance and quants 
Now concerning the BT practice questions, some of them are hard to an extent that there’s no way you’ll get them in the exam. So you spend a lot of time trying to solve them and you end up going thru a lot of tough questions BUT in the exam you’ll get a lot of easier questions that you dont know how to solve because they werent covered in the BT material.
Schweser’s questions may be easier but usually they cover what you will get in the exam. You don’t see Schweser dedicating a whole section for a notion that you surely will not see in the exam.