Hello Oleg,
text in SAP GUI for Java is taking advantage of Retina on Mac on the old Apple JVM (1.6). Java 7 from Oracle does not support optimized rendering for retina. The latest Early Access version of Java 8 comes with support for retina and text in SAP GUI for Java looks great. It is planned to support Java 8 with SAP GUI for Java 7.40.
Best regards
Rolf-Martin