Reasons to Use QPad
QPad can open very big files, or binary files.
QPad has many programming features, including "go to definition", auto-completion, code folding, build / run, and more.
QPad can do fancy regexp stuff without the learning effort. You can create a regexp by clicking the "fold" button in the search bar. Also, when you edit a regexp match, QPad can automatically generalize the changes.
QPad detects common CJK encodings. Those Japanese game manuals won't appear garbled any more.
QPad has really fancy typesetting if you choose "Markdown" in the language menu. It can make novel-reading and blog-writing much more pleasing.
QPad adapts to your screen resolution. Things won't become ridiculously large on a cheap projector, or ridiculously small on an Ultra HD display.