Having 60 days return why not just order it and try it out.For some reason i thought the tablet part/screen of the device would have longer battery life. I spend a lot of time with my tablet vs my laptop or iMac. I'm in no hurry so i can wait and see what happens and or what else is released this year. I did also want the Surface Neo, however that seems to have been pushed back until next year, altho the Duo is still rumoured to be coming this year.
Even if i don't get the Book 3, i'm still looking at Surface devices, even if it's the Surface Pro X. For the time being my iPad Pro is still working (not sure how long for) and the longer i use it, the more i'm getting my moneys worth i guess. I'm not sure when Microsoft typically update the Surface Pro line up, but maybe i'll have another go at one of those.
Although reviews may be useful, nothing can replace hands on experience, and I do not mean here a 30 minutes play time in a store.
Just order it and if it doesn't work out, return it. 60 days is plenty.