I ran through the EPA and overall the premise of it isn't bad, it's just that it's overly huge as in 50% of the space is not used effectively, ending up redundant and taking away from the overall impression of the place. However once you know where to go and who to talk to and take into consideration the rewards you get from the blue level, it all makes up for it. The quests themselves are just very streamlined and the solutions are uninspired. How so? Well, you are a scientist, mechanic, elaborate talker, problem solver and a killing machine but you can't figure out to fix the lights before talking to the quest givers. It's that some quests that should be more flexible are scripted to be more rigid with only one specific solution which is making the player jump through hoops in a specific order. It's understandable with quests that just wouldn't make any sense being completed in a non-linear fashion (you can't really deliver westin's holodisk without getting the quest nor finding the object; you wouldn't even know of the existence of such an items) but with broken machinery it doesn't make sense that a mechanic would be clueless as to how to fix.
the EPA is just too big for its own good really. With all the available loot and quests I can see it all being on one single floor with different coloured hallways. Some locations in the EPA are completely nonsensical: why is there a massive room with leaking vats and blood bugs, how did the vats get there? There are no freight lift in the vicinity, there is no way that a forklift would get in there and who put the bugs in that one room anyway...
The architecture is wonky in that regard.
The loot is super good in the EPA, the +agi syringe changes everything and the training from the NPC makes the trip worth it. It makes a whole new build strat viable (I might make a proper runthrough soon: premise is that you can squeeze out an extra attribute by switching out Small Frame for Fast Shot at level 27, losing a point of AGI in the process but then taking the syringe and effectively gaining a bonus rate of fire perk with extra carry capacity.)
Regarding Sierra Army Depot: that place seems haunted and ominous and gives you the impression that you are being watched as soon as you interact with a console and walk by rows and rows of idle robots. It's perfectly sterile, untouched and seemingly harmless at the first glance. The facility isn't too big and the exploration is worth it as you get plenty of loot out of it (books and combat armours for those dermal implants and a bunch of drugs to boot). The whole facility is somewhat of an encapsulation of the atrocities that were going on before the war and the wickedness of the scientists who were prepared to sacrifice whatever it takes to get the upper hand. The SAD is probably the most eerily serene location in the whole game. It's not really about the NPC nor the the loot that you get out of it but it in stead sets the tone for a bit of the game. You are no longer in a grimy dirty shithole crackpot-laden town with lots of various personalities to interact with. The SAD is one of a kind location in the game and as far as I know it works as intended and tells a story of what transpired between the walls.
Now, the EPA is a bunch of things thrown together trying to be your generic run of the mill science place which isn't really all that interesting. The depressed robot is quirky, okay then. There is a hologram that is a tough badass but who crams out of place german phrases into sentences for no good reason, thus breaking the character he is trying to portray. That authoritative down to earth power-armoured dude throwing that "Schweinhund" around like hot potatoes; it's just bewildering how inconsistent, yet at the same time generic the characters are. It's a clown fiesta, everybody is incompetent, broken or both. Isn't it kind of meh that there are 6 holograms that want you to do the same thing: repair that thing, essentially do the same quest three times.
There's that green level door password: I have 10 luck, shouldn't I be able to just luck through and guess ABRE?
Why can't the rope for the lift be on the same map?
Why can't I kill anything with the solar scorcher on the premises?
Why don't levels with the same floor number cross over with one another?
Why are there mantis in the basement and how do they survive?
The blue level is really good for the xp though. There aren't enough areas like Mariposa where you can just go buck wild on enemies as you explore and continue onwards; the blue level does deliver some of that goodness.
Overall, as I'm going to continue doing Hard/Rough tough as nails playthroughs (no san fran shortcutting) of Fallout2RP, I'm going to visit the EPA either way just because of the syringe, xp and skill boost from the NPCs.