As I said before, I've played over 500 games. I *often* buy RoH first in all-random games. Now if all-random games are 1/3 of the games I play, and *often* does not mean *always*, you should be able to figure out that I have bought the suggested items in the majority of the games I have played.
Yet, I don't see the huge difference you or zeze profess, in fact I feel that I do better with an RoH than without, on average.
Chances are , you don't see a difference because you are bad. Not that there is anything wrong with that, but a capable player is far more effective in the lane with more damage, more HP, and the occasional regen than a player with less damage, less HP and steady regen.
The regen isn't something you should rely on. You take bursts of damage in Dota 2, not some constant slow damage. If you survive a gank attempt and are left with say 100HP, you are out of the lane. You can either go back to base and heal or stay as far away from the other player as possible while waiting to regen ever so slowly. You generate 300 HP per minute from RoH. That is a lifetime of losing XP during the laning phase. If you survived the first gank, you won't survive the next, because their skills will be leveled up and you won't be at full health.
Yes, on certain heroes, in certain situations, RoH isn't a bad choice (but certainly not first). If you are long lane Anti-Mage, after you build boots, RoH is a good option. You can continue lane presence while building your Battle Fury or Vanguard depending on your build.