ALL of them are a P.I.A. when it comes to fixing the thread, especially when you have poor eye-sight and were born with ten thumbs. For casual use however, I'd look at the older BOSS unit by James George (the originator to such devices --
http://www.thisismagic.com/html/invisible_thread_reel.html). The small size makes them quite versatile when it comes to placement and application.
TARANTULA is an interesting idea but in my opinion, not as "practical" as the Spider Pen . . . It is excellent in certain settings and with a bit of practice, can leave you clean; but that's the rub, it's something you must ditch vs. the Pen that is in full view or a concealed unit like the above.
I'm not a huge thread worker simply because I'm a klutz with the stuff (picture an elephant learning fine embroidery or how to spin a spider web), but given my experience with what's out there, the BOSS or the Pen would be my first two choices with the TARANTULA as a great way to accent either of the two (it breaks the pattern when it comes to anchor point; by using two reels you're able to remove the patron's ability to reverse engineer things. I've been a huge advocate of multiple methods for decades now.)
Hope this helps
