Juusou Kikou Dancougar Nova

Similarity : - Team works is the main key when fighting - Mecha unit have a time limit to operate (Dancouga Nova only have 5 minute & Luxon-Bradyon only have 10-15 minute) Different : - Different theme story - Different enemy 

- Mecha unit in both anime is not single unit but consists of several parts - Although consisting of several parts, there are units that can fight individually (Earth Engine Ordinary & Nova Angel Humanoid Mode) - The main character is composed of one group consisting from 4 members (Mid-Summer Knight & Team D) IMO, If you like Super Sentai Series (Power Ranger in west) you will be like this  

Both have a common element in which the main characters use their overpowered mechas to intervene in conflicts. Dancougar Nova is more episodic and comedic, with super robot action, while Gundam 00 focuses more on military drama, the relationships between the various factions, and features more real robot action. 

- The main character is composed of one group consisting from several members (Team Rabit have 6 members & Team D have 5 members) - Ange Kuroki (6th Member of Team Rabit) & Eida Rossa (5th Member of Team D) joined The Main Team later in last arc. Also both character have a problem when first joined with The Main Team. - The Main Base of both team (Rose Colony & Dragon Hive) can be transformed into Single big attack unit - Both anime have alot similar characters, Example : Rin Suzukaze & Tanaka, both character is commander of Team Rabbit & Team D - Both Mecha unit was developed using alien technology who also serve as main antagonis (Will & Wulgaru) IMO, If you like Super Sentai Series (Power Ranger in west) just like me, you will be like both anime  read more 

- The Main Teams from both anime consists of people from different background Jersey Club - Different planet & ras Team D - Different status social - Mecha units from both anime have big power but unfortunately in some point that power can making them become anti hero (Team D) or antagonist (Jersey Club) - Transformable mecha units 

Because if for some reason, you actually liked this series, Dancouga Nova is the exact same thing all over again. But now with Gravion references. 

Mecha unit in both anime is not single unit but consists of several parts. The main team is composed of one group consisting from several members. Story tells about invasion "alien", to prevent more victims, aquarion & dancougar nova created just for that. To control aquarion pilots must connected there mind and body into a single coordination, dancougar nova also have same condition but with "little exception". 

Similarity : + Transformable mecha units + Each mecha units can be merged into one single unit Different : + Webdiver set in Virtual MMO + Juusou Kikou Dancougar Nova set in real world 

The story are both about protecting the Earth from Aliens. Both mechanic design are by the same person