There are two types of people who would be interested on watching aquarion logos:
the ones who already saw sousei and evol and want to see the new aquarion anime and the ones who doesnt know about sousei and evol but something on logos catch their eyes. By the way Im from the first group.
For the former logos will be a little dissapointing because it doesnt follow the story of the previous sousei and evol, its a spin off in a different universe with some elements in common with the previous seasons and for the latter it really doesnt matter and can view logos by what it is, an original mecha anime on its own right.
To be fair evol concluded the story very well so a third season with another 12,000 years time skip could have felt a little bit too much forced so start a new story was a good choice.
Character design, mecha desing, plot and music all take a change from the original works but, some basic things that make aquarion be aquarion are still there like the fusion orgasms, references to whatever happen 12,000 years ago, a somewhat well played love triangle, and the silly plot, but other things changed for good or bad and made logos had its own identity.
Starting for the character design it took a weird turn, I dont know if they changed personal or what but the characters design are very different from what I see on sousei and evol and sometimes it looks somewhat... not bad but is just not enough appealing, for the personalities all can I say is that they start a little akward but they have a good enough character development.
With the mechas it was something different they made cool robots, but for the aquarion veteran fans watching the aquarion fusion be a rabbit or a firefly-like thing would be a little weird, but still mechas and also word monsters are well designed, what would be expected from a mecha anime.
The plot its still as silly as the previous series so there is not much problem there, is soon noted that they have all or atleast most of the writers of the original series working here.
And for the music all can I say is WHERE IS AKINO!?!?
Dont get me wrong the openings that mayn did are catchy and go well with the anime but an aquarion without an akino opening doesnt feel 100% aquarion you know what i mean?, but again for the new ones in the franchise this doesnt matter so good for them, for the endings and soundtrack in general all i can say is that they are good and go well with everything else.
Overall I cant stop comparing logos with sousei and evol but doing so make me realize that logos its a good, pretty decent mecha anime that refreshed the franchise and I really enjoyed it.
In conclusion if you are a fan of the previous aquarion just take in mind that this is a different aquarion, if you havent see the previous ones if you like or are interested in this one give them a try before or after watch this one, is more of the same but a little different.