My recent experience with HARP (with players totally new to the game) both differs and is in-line with the OP:
The first session, the PCs caught a bunch of goblins sleeping - literally. So, the "combat" wasn't long, drawn-out affairs. Dead goblins everywhere.
The next session saw them dealing with a ghoul, and the ghoul was totally aware of their presence. For the first few rounds, the fighter was forced to fight the creature single-handedly, because a doorway blocked the others from helping out. (I even ruled that the mage had to make a 'to hit' roll to touch the warrior in order to cast Haste on him, not an extremely difficult roll - but the fighter was swinging a broadsword around, one should be careful in such situations - though the mage managed to fail it anyway.)
The fighter, being a smart guy, used most of his OB to defend with (making the ghoul need a roll in the 80s in order to hit at all), so his attacks were appropriately limited in success. For a while it almost seemed like we were playing D&D, a few hits here, a couple there. But, then the ghoul got a lucky roll (96+67 = YIKES!) and the warrior was stunned, bleeding, and at negative mods to do anything. Of course, this made him fall back through the doorway, thusly exposing the ghoul to everyone else. Well, it still took them 4 or 5 more rounds (for a total of 9 to 10 rounds) to finish off the ghoul. A good fight for young adventurers.
Overall, I think the fight went well, and pretty realistic. One of my issues with RM (like Shadowrun) is that it is entirely more deadly than real life, like a lot. Yeah, one aspect of that is the all-or-nothing methodology used by both Players and GMs (through their NPCs - something I am going to try and get away from), but a big part of it was/is the deadliness of the crits. I do think there should be results that end in unconsciousness, so that players cannot "fight to the last" EVERY TIME. (Come on, people! I get it. CONTROL, CONTROL, CONTROL. But sometimes you don't have that. What is the difference between a spell taking control of your character or an extreme injury?!? I think none. Plus, there could be a cool, dramatic storyline with your character dealing with his bout of "cowardlyness".)
BTW: for the first session I used the crit tables right out from the main HARP book, but I switched to H&S for the second session - and I will be using H&S for the remainder of the campaign.