Hmm, wouldn't Atheling Mantle also be best for TPing?
Pretty sure that depends on total haste. Lets say you've got all this stuff for the rest of your gear
AF3+2 Head +6%
One of the +4% haste hands(Timarli Dastanas, Ace's Mufflers, or even Dusk +1)
Twilight/bullwhip belt +7%
ACe's Hose +4%
AF3+2 feet +5%
That's the 26% gear haste that, correct me I'm wrong, is the amount you actually need to cap out gear haste. In this situation, which is pretty much top of the line, yeah, Aethling is clearly the best since Lancer's Peleraine isn't doing anything for you. Assuming though that you're not as optimal as above, like most of us are likely to be especially at this point, Lancer's Peleraine is probably going to be more powerful depending what other haste you're getting. I mean, Blitz ring is in demand for a reason. Or was anyway, I'm not sure what the market is like now that full AF3 sets are out there, lots of jobs are able to cap gear haste without it now. My current set for example goes like this:
AF3+1 head 5%
Homam hands +3%
Goading Belt +5%
Lancer's Peleraine +1%
Ace's Hose +4%
AF3+1 feet +4%
So I currently have 22% gear haste, I'm not sure if aethling would be better than 1% haste or not, someone else would have to crunch the numbers. As I +2 my head and feet though I imagine peleraine stays stronger until I can cap without it. And then there's other factors, like x-hit builds coming out of stuff like the store TP from being able to keep Goading Belt, and whether or not that TP gain outweighs 2% DA on Twilight belt, in which case I'd still need the peleraine to be able to hit gear haste cap. Of course, this is all assuming the benefits of the stat boosts in abyssea, given some of those pieces have negative stats(-10 acc. on Ace's Hose, which may still not be a problem outside of access to RR thanks to Acc bonus III, and the -Store TP on Ace's Mufflers). Assuming we eventually move out of abyssea again, different setups may be useful again, but that's all going to be wait and see until we hear what SE are going to be doing for the bumps to 95 and 99.
tl;dr it's not cut and dry, and is in fact like most things highly situational, and someone with more time on their hands would have to do the math