I've been playing with 12 gauge pumps for almost 30 years now.
On my 18th birthday I ran out and the first gun I purchased on my very own was a Mossberg 500.
I used that thing for over 20 years and never had one single problem with it.
I have also had Remington 870 shotguns over the years.
As a matter of my own personal preference, I tend to lean more towards the Remy (as you would notice when you looked at the number of Remingtons I have compared to Mossbergs).
With that said I like them both very much.
Now when it comes to the uber short shotguns, I like the Safety Harbor KEG12s.
I looked at Serbus... liked the SHF better.
I read about Serbus... liked what I heard about SHF better.
I tried to contact Serbu via email and phone... they must not have wanted my business very badly.
Safety Harbor... I can get Peggy on the phone whenever I want during normal business hours.
And if I need Walter, it only takes her a minute or two to get him on the phone.
In my opinion, the service you get before a purchase is pretty indicative of what you will get after.
I have been very pleased with Safety Harbor's service pre and post purchase.
As far as my KEG12s go, the 870 Police Magnum was my first and I probably would have stopped with that one.
Until I found out about the Black Aces Tactical Mossy 500 mag fed receivers!
If you're happy with only 3 rounds then get the Remy.
If you want up to 20 rounds then get the BAT Mossy 500!
By the way, they're uncomfortable to shoot and deafening even with double hearing protection, but they're a hell of a lot of fun!!!