Emulate tabular vertical spacing with parskip package

I would like to emulate the vertical spacing of tabular without using tabular. When the \parskip package is used, using \par leaves too much vertical space, so I thought I'd emulate it with use of a \newline:

Now, this seems to work just fine, most of the time. But am running into a Missing number, treated as zero which I suspect is related to using a \newline. Plus I recall something about using a \\ or \newline outside of a tabular or array type of environment being a bad thing.

So, my question is: Is using \\ or \newline a bad thing, and if so, why? What alternative ways can I emulate the vertical spacing of tabular when using the parskip package?

Code:

\documentclass{article}
\usepackage{parskip}

\newcommand{\ColumnA}[2][l]{\makebox[2.5em][#1]{#2}}%

\begin{document}
Output using \verb|tabular|:

\begin{tabular}{@{}ll}
abc & def \\
uvw & xyz \\
\end{tabular}

Using \verb|\par| leaves additional vertical space:

\ColumnA{abc}  def \par
\ColumnA{uvw}  xyz \par

\medskip
Emulating \verb|tabular|:

\ColumnA{abc}  def \newline
\ColumnA{uvw}  xyz \newline

\end{document}

• I'm confused: parskip (more or less) just increases \parskip to put space between paragraphs, if you don't want paragraphs with space between don't use it (or locally set \parskip back to zero? – David Carlisle May 5 '14 at 9:49
• I cannot see why the double backslash schouldn't be used in your case?? It is only a problem inside a paragraph with more than one line. – user2478 May 5 '14 at 12:38
• @DavidCarlisle: I am ok with setting \parskip locally, just thought that that it was recommended int the linked questions to not do that. – Peter Grill May 6 '14 at 4:01
• @Herbert: Thanks. I will use the double backslash then. – Peter Grill May 6 '14 at 4:01

As mentioned by Herbert you should use \\. It is no bad thing. If you really want to end a line, it is the right thing for you. In most cases it should be also your preferred way of breaking lines, because some environments redefine \\ to suit the current formatting.
If you search for something stretching your text to line end you should have a look at \linebreak.
My suggestion regarding parskip: Forget it. You don't need it. You want content which is not in distinct paragraphs, so linebreaks are sufficient.