Same problem here, Transcend MTS420 120GB not working properly, sometimes working, other times not recognized by BIOS.. only usable as a secondary drive and not good speeds at all.. After trying many tweaks I returned the ssd to the shop and bought Samsung 860 Evo 250gb, works great at full speed without any tweaks, just plug and play..
Only downside is you have to unmount the back cover and cut the 2242 ssd frame to fit the 2280 ssd in there.. but its easy and really worth it (but you probably loose warranty because there is label on one of the screws)
also crucial mx300/mx500 and intel ssd´s should be fine
