Lxtask left-aligns the text in each column. That is okay for columns that show pure text (such as "Command" and "User"), but looks weird in columns that show numbers (such as "CPU%" and "RSS"). It also makes for a generally "jumpy" appearance: namely needless on-screen activity, such as the redrawing of "%", "MB", or "KB" in a different place, just because the associated number changed a little.
The attached patch right-aligns text in columns from the third one ("CPU%") onward. That looks better, and reduces the amount of visual clutter.