Ok in my opinion here's how I look at my own modules. (Note I have extensive playtime in them)
1. Ruined Keep of Agramar:
Ok yeah this one is intense, requires a lot of tactics, but it is seriously reminiscent of the old Icewind Dale and Baldur's Gate. Its straight up 1st Edition level encounters, requires a great deal of tactics, and requires a lot of Force Multipliers (aka Fireballing Wizards, Spiritual Guardians Clerics, Hypnotic Pattern and Monster Summoning Green Mages) . It is intense, and every bit as intense as the Icewind Dale games are.
2. Temple of Evil on Witch Mountain
I can't help it, this is just such a fun little 1st level module. The music, just really builds the mystery, it feels so much like the actual Temple of Elemental Evil game, I consider this one of my best achievements since I was really going for the Temple of Elemental Evil vibe in this one, and I actually key'd the encounters and "feel" directly from the 1st level of that Module which I was looking at while designing it. The REAL feel of exploration and the feel of being in an old abandoned Temple of Evil with all the history of what happened included. If I were to rate it on pure design alone, I would even give it higher marks than Ruined Keep.
3. Halls of the Ogre Lord
I intended to design a kind of "Against the Giants" feel with this one. Outside of Temple of Evil on Witch Mountain this one has probably the best map layout. This one has a really cool little underground city design. And unlike Ruined Keep of Agramar, this one the monsters are much stronger, so even bringing a lot of Force Multipliers isn't really enough, you need some seriously strong Fighter/Paladin types to bring them down along with those. It does play a lot like the old Against the Giants Series modules and you can really feel it. If this included the Second level which is Halls of the Ogre Lord part 2, (due to bugs in the current toolset making it a multi-level module is not possible at this time) I might be tempted to rate it higher than Temple of Evil on Witch Mountain otherwise as you could have crept through the Halls in a kind of stealth mission like it was intended.
4. Crypt of the Wight King
Honestly this one is a good solid module, beginner style with lots of secret areas, and really feels like you're creeping through tomb. Plus multiple ways to take on the encounters if you utilize those secret doors and can find them. Its got a lot of the old 1st edition style tricks/traps in it as well. Its just unfortunate that traps aren't really working as intended yet so any trap detection is an automatic disarm. This one really is for a beginner or a newbie even though its 5th level. The encounters are not overly strong, but are fun and allows you to use cautious mode a lot. This one isn't as hard as the others, but it allows for some good dungeon crawling.
5. Hidden Shrine of Dramacht
I do not know what it is, but even though this one is well designed and has some great encounters and good backstory in it.... I just don't like this one as much as the others. There's nothing wrong with it, its got some really cool stuff in it. But it just doesn't get me going the way the others do, but then again all the "surprises" don't surprise me, since I know they're coming. Combat can be intense, but its not quite on the level of either Ruined Keep of Agramar or Halls of the Ogre Lord. While I'm sure others disagree with my personal choices in these, this one just didn't quite pump me up the way the others did.
6. Haunted Keep
Honestly Haunted Keep was intended to be a test module for a multi-level module design while bug reporting in the forums. It was never intended to be released. It just came out so well I decided to put it up there anyway. It IS the straight module from the Tom Moldvey's edition Basic Players Handbook sample module from 1981. Its a good solid Basic D&D module. But due to limitations in the Beta Dungeon Maker it cannot be completed as designed. So I had to take a few liberties. Still I enjoyed my playthroughs of it.
Now... to be honest with you... the Modules were intended to be played in this order...
Temple of Evil on Witch Mountain (which when adjusted would get you to 5th level)
Crypt of the Wight King (1st Council Mission, getting you to 6th level)
Hidden Shrine of Dramacht (2nd Council Mission, getting you to 7th level)
Ruined Keep of Agramar (3rd Council Mission and Finale or wrap up to 8th level)
Halls of the Ogre Lord (Bonus Mission from the Council after beating the Orc Lord in Agramar)