Given that the Soviet Union only occupied the Baltic states only about a year before the Germans, and Reichskommissariat Ostland was established as a distinct area, were they treated any differently by the German administration?
One thing that really stands out is the way the Lithuanians were very willing to join the Germans in their war to exterminate Jews in Eastern Europe. This did not mean the Germans were any easier on the Lithuanians than other Slavic nations the Nazis overran during World War II. The details can be found in the book "Bloodlands: Europe between Hitler and Stalin" by Timothy Snyder. The Baltics states were treated harshly by the Germans, but the Poles, Belorussians and Ukrainians were treated even worse.
Just to add on Lithuanians are not slavic, but rather part of the Balt ethnic family, like the Baltic Prussians (before they got taken over/killed by the germanics).
Bloodlands is a really good book and OP could do well to look at the source list and go from there for further reading there are many excellent secondary sources in there as well.
To also answer the question in the Baltic states today it is generally seen as having just been taken over and shuffled around. Those who collaborated with the Russians at first faced consequences once the germans took over and vice versa.
Overall it is seen as a pretty dark part of Baltic history with no real "good" side, just two bad choices.