Both of these revolve around a highschool boy's daughter arriving from the future in an effort to change said future. The boys (neither of whom even have a steady girlfriend yet) each find the situation quite difficult to believe. In both cases, the daughters cause quite a bit of chaos during their efforts. Mahou no Iroha is magically oriented while Little Jumper is technilogically oriented.
Those two series have a similar plot. In both a girl comes from the future and tries to help her future father meet with his future wife. While both series have some action in them Little Jumper is much more action orientated. Both series also future some subtle romance between the guy and his future daughter (rather than his future wife). If you read one and liked it, you'll probably like the other one as well.
In the future, Earth has a major problem: over-population. To combat this threat, nobody is allowed to have more than one child. However, this isn't a permanent solution, so scientists have searched long and hard for the root of the issue, and in the end, they found it: Junta Momonari, a mega playboy who, in his time, impregnated one hundred women! And so, Karin Aoi, a DNA operator, is sent back to the past to inject Junta with new DNA that should solve the problem once and for all... there's just one problem: Junta has a serious allergy to girls and throws up whenever he sees them! Regardless of Junta's lack of symptoms, Karin must carry out her mission; and that's where things start to get interesting...
In both stories, a girl/woman from the future goes back in time to alter a tragic future/future event by changing the DNA of a certain guy in the past. Things might turn out quite different than they intended though.
Both manga are time travel themed romance series. Both also feature a fair amount of action and in both the main couples try to overcome certain difficulties in their relationship (*cough* incest *cough*, but not quite). If you read one, you ought to read the other, as you will most likely like it.
Both series (well, in Tenshi no Okurimono it's just the titular oneshot) revolve around a guy who meets his future daughter. The girl tries to help the guy meet (and become a couple with) his future wife. In short, the plot is similar. On the other hand the style of those series is very different. Nonetheless if you found the story interesting in one of them, you should check the other one too.