have to say that samsung ms25/28 are far more advanced in term of features. Reliability seems good for both. You can play every game on both, so if it is all you want, they will both serve you well.
If you want to play with all the bell and whistle coming out, then definitely the samsung is far ahead.
-no booktype require
-sl for xbox 1 title
-slow/fast read speed...
and a lot more.
also I will direct you to this post
Also remember that if you do not get a sh-162c drive in your pc to backup your games and that you want to open your 360 each time you do a backup, the hitachi cannot extract backup. Just IMHO, and considering how convenient it is, I feel everyone should get a SH-D162C rather than opening its x360, but that is just me
As far as the flashing is concerned, if it is for a new system both have their +/-. Overall they are the equivalent IMO.
If it is for a replacement drive, then I find the samsung is a lot easier to insert the key+spoof+flash.
Hope it helps