I'm curious what your biggest problems have been specifically. I've been using Reaper exclusively for the last several months. I do quite a bit of chopping and editing in whatever I work on, plus a decent amount of MIDI stuff. Previously, I would use either Sony Acid or ModPlug Tracker, but Reaper blows both of those away.
My biggest gripe by far is that handling edges of clips is a lot harder than it should be. When you have two adjacent clips, you might want to do something simple like crossfade them into one another, or change the fade. However, depending on your cursor position, it can be ready to edit in one of four modes, like adjusting the fade, resizing one media item, resizing both media items, etc. It depends on pixel-perfect precision to enter the right mode sometimes.
Volume control had the same issue for me. Luckily, I came across
this tip that lets you adjust volume with the mouse wheelI'm also not completely used to how the mouse wheel affects the interface. A lot of the time, I expect it to scroll, even if I'm not hovering the left track list, but it just zooms the tracks. I figure I'll get over this learning curve eventually.
I like the way Regions work. I tend to create a lot of loops mostly from working with ModPlug for so long where you work in patterns. Acid didn't have anything to easily copy a chunk of time across multiple tracks. Reaper does, though. Just highlight the section on the timeline and hit Shift+R, and boom, new region. You can then hold control and drag it to copy it somewhere else.
If grid locking is getting in the way, I hold shift and drag the clips around to get them in the exact right place. If there's a small spot that I can fill in, I can usually drag an item chopped down to that spot's size into it, then hold Alt and drag around to find a position within that recording that fits into it well.
Grouping tracks together has also been excellent. In Acid, you'd need to set up a bus for every group, then route your channels through that bus if you wanted to control them all. In Reaper, you can just drag tracks around and organize them within others, which acts the same as a bus, but you can operate on them as if they were a single track.
