I'll lead of with a few simple words on the culvert loader/unloader.
New Pros: Looks nicer (condition) than a used PW piece. Nice they they added the infra red eye to line up the cars.
New Cons: Being DC motors, they are heavily reliant on the electronics for the "brains" that tell the motors when to reverse, engage (for unloader string), etc. Also, the motors are entirely contained up on the beam, so the actual part moving back and forth is MUCH larger than the PW versions, particularly for the unloader.
There is probably more to say than that on those 2, but I figured I'd start the thread off with a reply.
Also a thought on 445 switch towers: the original PW (and MPC remake, along with burning switch tower from 1992-ish) used a string on a pivoting arm to link the motion of the man on the balcony and the man on the stairs. Action was : solenoid activated, man upstairs goes inside (starts outside until activated), man on stairs descends (illusion that it's the same man). More recent ones that replaced the string with a geared mechanism (the 6-12917 from 1996 and all the burning variants since then), I am pretty sure all start with the balcony man inside, and the stair man at the top. So when activated, both men come out. (there is also an opening door, which on the string linked ones, I believe is just an opening, no hinged door).
445 new (1996 +) Pros: No string to get hung up or saw through the hole in the wall that it would travel through.
445 new (1996+) Cons: kills off the illusion that it is the same man on the balcony going inside and then descending the stairs.
(I could probably go on a tangent with differences in the original burning switch tower and the more recent remakes, but I'll hold off on that. . Since the burning one didn't exist in PW., it might be a bit outside the intent of your topic.)
Also, just my opinion, but I'd recommend changing the thread title to something like "Accessories - Comparisons of PW vs. Modern Remakes". The current title could mean a lot of different things.