Hmm lets see, spend $74.95 on a dry fly line, or $89.95 for one with InTouch series.
The perception has the same stretch as all the InTouch series, it is the $75 lines that have more. Taper will be different then the Gold (which is different then the Grand). If you decide you really want the Perception over the Gold and Grand, then go for it. However if you find out you want the Gold or Grand, I would save the $15 and buy the regular series for the reason below/
I think is that Rio is making suckers out of a lot of people. Unsurprisingly, as part of the Farbanks group they have a similar business model to Sage. difference of course is that lines are constantly getting changed as opposed to rods. If you look on the stillwater side of things, the Connectcore in a density compensated sinking line with built in hang markers is only $79.95. So I am going to bring up the new InTouch camolux and the older Camolux. The older camolux, which was translucent colour, was $74.95. The new one, which is very visible but a great line in other applications is $79.95.
Now I have been very happy with my Rio fly lines, I own a discontinued Trout II that is remarkable, the InTouch Camolux (warranty return on the Old one, loop broke [very good experience, sent it in and no questions asked got a new one back), and the Skagit Max. Rio makes solid lines, I just do not believe the no stretch is worth $15 more then the same line tapers without the connectcore.