Although fifth generation fighters offer benefits such as advanced technology and stealth characteristics, they have their drawbacks. Huge costs and constant maintenance are required to keep 5th generation fighters operating to their potential. Because of these resasons, 4.5th generation fighters such as the Eurofighter Typhoon and Saab Gripen have become increasingly popular. Offering performance on par with 5th generation fighters, minus certain extravagant technologies such as stealth, the 4.5th generation fighter serves as an effective interim aircraft until an air force can afford the money or resources to purchase more luxurious types. Sukhoi's Su-35 Super Flanker (NATO designation "Flanker E") took the world market by storm when it proved able to challenge and defeat any aircraft in the East (and West) except for absolute top-of-the-line fighters such as the EF2000 and F-22. The direct derivative of the Super Flanker, aptly designated the Sukhoi Su-37 Terminator, was only intended as a technology demonstrator but is one of the most manoeuvrable aircraft ever built.