Haven't tried it but this is from a review:
"Flavor Description: Artificial strawberry base with an attempt at rhubarb. It has some similar flavor aspects, but it is missing that sharp tangy tartness. And it has a very noticeable chemical off note. The fruits do blend and balance well without either overpowering the other. It's just a little closer to celery than rhubarb. Not getting crust at this point, and not sweet or sour enough. With the longer steep this has really blended well and matured into a great blend. The strawberry and rhubarb is balanced well, and has turned into a sweet and slightly tart pie filling. The strawberry has lost any artificial taint and is cooked and sweetened. The rhubarb left the celery behind and is a very authentic cooked rhubarb, but is missing that pronounced tartness. On the exhale I'm getting a light flour crust. It's very good, but not strong enough to balance the fruit."
My experience with PUR is they are not strong so don't be afraid to mix higher %. I have PUR Boysenberry preserves and it really changes after a steep (better) so don't judge yours to hard until it has time to steep.