For handguns MD easily.
With the shell casing law (only NY also has it) many guns became illegal (new guns only). For a while guns w/out the casing could be fired at a state police lab so all were available but they stopped that "loophole".
Now we are a couple days away from the built-in lock law. With this law any gun that doesn't have a built-in lock (as I understand the regs are still unclear what that includes so what may be legal when the law 1st goes into effect may become illegal if the law is "re-interpreted" later) that was made after Jan 1, 2003 is illegal to sell here. That makes almost everything illegal (only S&W and Taurus offer the locks across their entire line, HK offers them as an option I think, Springfield will have them on their 1911s, some others may have them now or develop them in the future but...). Used guns look like they'll be ok (though I guess the law can always be re-interpreted by our AG who is on record against private ownership and has stated that he will put the most restrictive interpretation on any gun law he can which brings us to...).
There is a federal law making gun ownership illegal for anyone convicted of a misdomeanor who spent a year in jail, at least that is the intent. The way it is interpreted here (and only here), if you were convicted of a misdomeanor anytime in your life (even a bar fight 20 years ago) that COULD have resulted in a 1yr jail term or longer (almost everything provides that as a possibility) you cannot legally own guns and guns are being confiscated (see the archives at TFL and you'll find threads about it).
There is a 7 day waiting period and state police check. They keep the paperwork but there isn't official registration here
.
CCW is virutally impossible.
One must watch a safety video to get a card that states you are allowed to buy guns.
One purchase every 30 days is the limit, unless you get a collector's license.
Private sales are regulated, must go w/ purchaser and gun to state police barracks for proper fees to be paid and background check to be started.
On the bright side no license is needed, no
real safety course is required (yet) and there is no
official registration (though the way the DC sniper investigation was handled should dispel the myth that there isn't real registration).
Long guns aren't bad here however (except "assult rifles" like AKs and ARs, which face the same restrictions as handguns). No waiting period, only the federal "instant" check, no limit on number in a month, no built-in lock law (I think) or shell casing law (yet), class III is legal, etc.
So for long guns I guess CA (which doesn't get it for me overall due to better handgun laws and possible CCW in some counties) and NJ (better handgun laws) are worse.
Which is worse overall, NJ, CA or MD, don't know.