When Tien and all that fought the Ginyu Force on King Kai's planet...I believe that was anime only filler (plus most of the King Kai scenes in general are filler). I'm not sure on this forum if filler is allowed or not so someone will have to tell me that.
http://dragonball.wikia.com/wiki/Filler Scroll down to the Frieza Saga about 2/3 of the way down.
Even if it wasn't filler though being able to beat the ginyu force from king kai's training (especially since he didn't even teach them kaio ken or the spirit bomb) is so stupid, however that's obviously just my opinion and not relevant to the topic.
In the Saiyan Saga the highest power level Krillin shows is 1770 while Tien is 1830 so Tien was stronger.
In the Namek Saga Krillin after Guru Power up 14,000. Just before they fight Frieza Krillin's power has jumped up to 75,000 inexplicably.
There's no power listing for Tien at all for the entire Namek Saga or beyond. (everything sourced from V-Jump Magazine or the Diazenshuu Guide).
This is purely conjecture at this point from me as there is no more official information.
During the Cell Saga I actually can't think of any Krillin moments or feats that he displays except I remember him throwing a destructo disk/Kienzan at Perfect Cell and it doing fuck all.
Tien obviously displays the feat of holding Cell back with his Neo Tri-Beam however this was using up his "life force" which makes it unique in the fact it literally is killing the user and it didn't actually harm cell in any way.
Ultimately they both had little effect against Super Perfect Cell in his final moments and I come to the conclusion that we'll never know who was actually stronger but based on the very few "feats" they have during this saga I'll give it to Tien.