I found many, many helpful things on tex.stackexchange for pgfplots - thanks for that!
But i can't figure out how to:
- insert a new line after "without" or "with"
- hide value 0 or the whole bar
- change the x tick's so there's no decimal power ([10^..])
- prevent nodes near coords of beein plottet outside the chart
the two charts:

and the sourcecode:
\documentclass[a4paper]{report}
\usepackage[english]{babel}
\usepackage[utf8]{inputenc}
\usepackage{tikz}
\usepackage{pgfplots}
\title{Tests}
\pgfplotsset{counter_barchart/.style={
width=0.85\textwidth,
height=5cm,
xbar,
xmin=0,
xmajorgrids = true,
tick align = outside, xtick pos = left,
x tick label style={ /pgf/number format/1000 sep=},
enlarge y limits=0.4,
symbolic y coords={Ass. Optimization,with Optimization,without Optimization},
ytick=data,
yticklabel style={text width=0.2\textwidth},
every node near coord/.append style={/pgf/number format/1000 sep=},
nodes near coords,
nodes near coords align={horizontal},
legend style={at={(0.5,-0.35)},anchor=north,legend columns=-1},
reverse legend
}}
\begin{document}
\begin{tikzpicture}
\begin{axis}[counter_barchart]
\addplot coordinates {(0,Ass. Optimization)(19243,with Optimization) (8898,without Optimization)};
\addplot coordinates {(7854,Ass. Optimization) (6652,with Optimization) (6548,without Optimization)};
\legend{Second,First}
\end{axis}
\end{tikzpicture}
\\
\begin{tikzpicture}
\begin{axis}[counter_barchart]
\addplot coordinates {(3985,without Optimization) (5456,with Optimization)};
\addplot coordinates {(5223,without Optimization) (11054,with Optimization)};
\legend{Second,First}
\end{axis}
\end{tikzpicture}
\end{document}
