I'm an insider with Win 10 and now running evaluation copy 10565. I made a post quite a few weeks ago listing the minor problems I encounted. However it is now running extremely well and I would recommend that you upgrade, if not now do it before you have to pay for it. I've upgraded two laptops and one desktop for two PC illiterate users one of them with learning difficulties and they are more than happy with the upgrade.
Win 10 is really nothing like Win 8 which I tried for a few days before binning it and as for the start menu well you can do various things as the attached photo shows.
I've been a big fan of Win 7, so what I did was clone my Win7 to another hard drive and update the cloned version to Win 10. I now use Win 10 probably 90% of the time, but at the moment save any work to a dedicated drive which can be accessed by both Win 7 and Win 10. I guess that shows I'm not totally committed to Win 10 just yet, but almost.
I hated the Win 8 start menu, even with classic shell, but with Win 10 you can change it quite easily as the photo shows.
I would advise that if you are eligible for the free upgrade to do so and if neccessary do the same as I did and do it on a cloned version. Oh and by the way, just in case you are not aware you can download it to DVD from
http://www.microsoft.com/en-gb/windows/windows-10-upgrade and install at you leisure
Harry