In both the Crimea and Eastern Ukraine anti-government troops, without identification on their uniforms, popped up supposedly from nowhere. Nobody had any doubt that the troops in the Crimea where professional Russian soldiers. They were highly disciplined, armed with the latest Russian equipment and well supported. It has been assumed by many that the Eastern Ukraine militias occupying government buildings are also Russian soldiers. Arto Pulkki at Suomen Sotilas, a Finnish Military magazine, makes a compelling case that the Ukraine militias are not Russian troops, but rather an assorted rabble of civilians and retired or reserve soldiers …

Here’s a brief summary of the radical materiel differences between the two cases:

• In Crimea all soldiers used modern small arms (5,45 mm AK74M, 7,62 AKMS, 7,62 mm SVDS, 9,30 mm VSS etc.) as currently issued by Russia, but in East Ukraine you see mainly previous generation AKS74s and AK74s from the 70s and 80s.
• In Crimea half of the soldiers armed with AKs were also issued with GP-series of 40 mm grenade launchers, as expected, but in East Ukraine you see practically none of these.
• In Crimea practically all of the troops, line and special, wore modern ballistic protection for head and upper torso, but in East Ukraine you see practically none.
• In Crimea 25 % of soldiers were armed with excellent 7,62 mm PKP/PKM light machine guns, but in East Ukraine you see no PK-series, only Soviet-era light 5,45 mm RPK74s..
• In Crimea 25–50 % of soldiers were also armed with RPG-series of lightweight disposable anti-armor weapons, but in East Ukraine you see practically none.

The videos comparisons are also convincing. The East Ukrainian militias appear both incompetent and undisciplined, a danger to themselves and any non-combatants around them. These videos are of East Ukrainian militias:

This is a video of troops in the Crimea (skip to about 2:00, its a long video):

Thanks to Pekka for the tip.