These anime are very similar, especially in their world aspects. Both feature a universe where there are multiple settled planets, each with their own unique customs and technology. Both feature very diverse and unique props, vehicles, and cultural designs. You will see props being used in these anime that are very unique. You could almost think that they are different stories about different people in the same world, though they have a slightly different feel. Iria is about a girl searching for answers about her brother who has disappeared, and her interactions with a strange creature that seems to have some political aspects surrounding it that are more than meets the eye. Outlaw Star is about a captain of a special ship he has acquired, (and his friends and crew) that are dealing with searching for something called the Galactic Ley Line, and having to dodge shady crime syndicate people who want his ship while searching for his goal. One of the things that makes these anime similar also, is that Gene Starwind and Iria are similar characters in some respects. For example, whenever they get into a pinch, they both use a lot of interesting gadgets to get out of it. However Outlaw Star is more of a team effort sometimes, and Iria goes it alone mostly, they're still very interesting characters in similarity. Gene is more of a grumpy hot head, and Iria is more of a sporty girl with a motherly side who is devoted to her brother, but especially in terms of their gadgets and such, there's a lot of similarity.
Both anime are very similar in some aspects. If you like one you would probably like the other.  read more
The world presented in both animes is very similar, in both the protagonists are bounty hunters of sorts, although themathically they have diffirent approach to the plot.Even if with some diffirencies, if you'd enjoy the diversity and comlplexity of the worlds, presented in one of the shows, go for the other as well.
Strong female characters working as bounty hunters is the main similarity between these two anime. Both are set in a sci-fi universe with some unique technologies and after watching both you will yearn for more.
If you like one, you will almost certainly like the other.
Like Outlaw Star, Cowboy Bebop shares some similarities with Iria, in that it is set in world with multiple settled planets, each with their own customs, and where space travel between them is cheap and common. Kind of a cyber-punky world. Where they differ, is that Iria and Outlaw Star, definitely have a more "far out" feel in that they seem very removed from our own world, like far future, or another galaxy. Cowboy Bebop on the other hand, clearly takes place in the future of our own present world, and includes references to the Earth, and so has some elements that tie it in with our own timeline. Cowboy Bebop is a story set in our own future, whereas Outlaw Star and Iria are much more abstract, especially Iria. However, they still share some similarities. And if you liked one, you may like the other.
One interesting similarity is that both Iria and Spike and Jet are bounty hunters. Wheras in Iria that's something of a side story, as her main priority is finding out what happened with her brother, in Cowboy Bebop it's more front and center as it's how they get paid. But both stories have many similarities both in worlds and in that the main characters are bounty hunters. read more
One of the main things that these two anime share, is very unique set designs. Both Nausicaa and Iria: Zeiram, feature some of the most unique set designs ever featured in anime. Many anime feature run of the mill buildings, or worlds that seem very similar to our own, but the toxic forest in Nausicaa and just the general world entirely in Iria, are very interesting visually. If you like anime with very unique set designs and world designs you will probably like both of these. They also share a main character of a girl who in many respects are similar in their feel. Nausicaa is more in tune with animals and nature, and is focused on her projects. Iria, is more sporty and care-free and devoted to her brother. But they both are about a story of girls who must find their own way in some aspects, though Iria is more on her own.  read more
Girls with big guns traveling in space working for the gov. getting paid to do dirty jobs, Dirty pair is more on the comedy side while Iria:Zeiram the animation goes on a far darker and more violent side. like them both!!
Both are sci-fi action anime from the 1990's. Both are action-packed anime with similar animation. Both anime feature a strong female main hero that kick ass going to another planet to track a dangerous alien life form that is a major threat to the galaxy.
Let's say there was one sole Knight Saber in Bubblegum Crisis and her name was, Iria. Both are fun sci-fi's with females that kick ass basically, they don't offer incredibly mindblowing plots, drama, aren't very deep or complex, or whatnot, but the quality is there along with great production values for their time with excellent action and sci-fi settings/designs. All around classic sci-fi.