Timeline and Timefactor owner here (also a Superdelay in case you want to add that to your possiblities...).
In terms of the sound, the Timeline is definitely the "warmer" and more organic than the Timefactor. It's not that it's better per-say, just different. I think which sound is more appropriate depends on what you want to use it with and the effect you want to achieve.
There are some things I do like better about the Timefactor. Every delay on it is a dual delay, so you get independent control over each, particularly the timing. This can lend it to be a bit more flexible in setting it. The Timefactor also has a better interface; everything seems a bit more immediate on it. And what I really like is the delay timing can be set via note length, as opposed to the Timeline which uses either ms or bpm.
The Timeline does boast some nice algorithms. For example, the "ice" setting is very similar to the shimmer reverb on the Eventide Space. As the shimmer on the Space is one my favorite effects, I think having that option on the Timeline makes it appealing if you have no other delay/reverb pedals.
Haven't used the loopers on either pedal yet, so can't really comment on those.
Btw, don't agonize too much over which pedal to get. After all, if you're anything like everyone else, you probably won't stop with just one.