I also started with LCWO, and made quite a bit of progress.
But when I was through with LCWO at 12 WPM, I changed my practice. I am now using ab iPhone app called "MorseTest", a sheet of paper, and a pencil.
While LCWO is well done, it has a few problems for me:
- You need to be online. Not ideal on a train etc.
- You cannot really do it on a smartphone and only poorly on a tablet.
- I found it helps me much if it's just me, a sheet of paper and a pencil. Sitting in front of a PC distracts me, and also closing your eyes for a moment to focus is impossible.
But the main reason I switched is that the net time spend listening and learning code is at least double as compared to LCWO. No loading times, no time spend reading how well you performed, etc.
Of course, you can also use LCWO that way - just copying to paper and typing in your results only every 10th run or so.
But I actually don't need LCWO to tell me whether I copied 92.3 or 95.6 % correctly. I can easily assess my progress during the copying (I almost never write down a wrong character, so the simple amount of blanks/missed characters tells me my performance).
Just my two cents.
PS: By the way: What I find most difficult are short characters, in particular "e"s before difficult characters, because they change the rhythm a lot and reduce the mS I have for decoding. So I spend extra time with "e"s, and observed that at some point adding a new character actually improves my performance, because more "long" characters give me more breaks to re-sync.