IMO the 20mm front axle is more of a performance upgrade than the extra 10mm of travel; that and the extra stiffness all round of the Pike in particular. I really doubt you’d notice the extra travel but the stiffness of the fork is quite noticeable, especially if you ride hard. But whether that is enough to justify the extra expense is up to you.
I managed to get £270 on eBay for my RS Revelations with Push upgrade, but these were only about 6 months old. You can always off set the cost of the new fork against the ebay price.
Having had and broken one set of Pace (as they were then) forks I wouldn’t have another set but I am a heavy rider and have a habit of breaking things. Plus since Pace were bought by DT I imagine the quality of their manufacturing has gone up.
Having said that, if you bought the Pikes from TF you have cast iron warranty and after sales support close at hand.