Years ago I bought the Fender Acoustasonic 150 (not available anymore) over the Fishman because they advertised it as a dual capable amp. They said you could play acoustic and electric, or acoustic and vocal through it. I bought it online and was not very happy with how my electric guitars sounded through it. The Positive Grid Spark looks pretty cool, but if you want one that you can gig with you might want to look into the Peavey Vypyr X 3. That one looks really cool too because you can play acoustic, electric or even bass through it, but it’s brand new and it’s not actually available yet.
The most important thing I would say is to go down to your guitar store and play through the different amps, to make sure it sounds good to you, before you buy it.