Well, this is like comparing 'Apples & Oranges' - Apple's TC is both a router & a storage device which works well w/ Time Machine on an OS X computer, while the Seagate is a wireless storage device only; SO, please outline your needs so that we understand how to advise - thanks.
You'll need to explain the purpose(s) of wanting to link your i-Devices via BT; this wireless technology is mainly used for pairing keyboards, speakers, & headphones; can also be used to establish a Wi-Fi Hotspot, but if your needs are to transfer files, then not a go - sorry; check this recent THREAD - if you have a specific question/reason, then ask. Dave