Progressive music is the hardest music to get into, given that experimentation is the norm of prog, more so in rock and metal. Now whether it is with a variety of different sounds and styles, or just becoming too technical with the instrumentation, it generally is enough to turn off those who are either unaccustomed to hearing such changes in their music and prefer either a standard 4/4 approach to their music, or just don’t like musicians experimenting.
 
But prog rock/metal are not just all about being different for the sake of being different, or being otherwise pretentious. Granted, some artists and prog fans in general tend to go into the pretentious style and sound more like skillful d-bags rather than actual musicians. But prog music is generally about either refining a formulaic sound to perfection by adding more ingredients to otherwise what can grow into a stale dish, or otherwise in that process create a new sound.
 
Prog rock/metal has this reputation that it is very hard to get into due to its long song length, shifting dynamics, musical technicality, love of experimentation etc.
 
Now prog is hard to define for prog does not have any standard sound.  You have bands like Iron Maiden, Uriah Heep etc are very much progressive in nature but not in the same sense as Opeth, Camel or Dream Theater which are 100%  “classic” prog rock/metal. Some bands don’t fall into the “classic” progressive label, but have such an undeniably strong influence that labeling them as such is not a mistake. The beauty of prog is that it does not have a standard sound, only certain characteristics, and this dynamism is what makes it special.
 
 
Best progressive rock/metal bands to get started on your prog journey:
 
1.  Pink Floyd
2.  Magnum
3.  Porcupine Tree
4.  Shadow Gallery
5.  Rush
6.  Dream Theater
7.  Yes
8.  Genesis
9.  King Crimson
   10.Jethro Tull
       11. Kansas
        12. Uriah Heep
          13. Hawkwind
    14. Caravan
    15. Tool
     16. Opeth
    17. Queensryche
    18. Mastodon
    19. Iron Maiden (2000s era)
     20. Death (post Spiritual Healing)