I've had a number of leftys over the years. Some converted safetys, some true left ejects, and a bottom eject BPS. I like the BPS and still have it, but it's a 10 and I rarely shoot it anymore. I have a Beretta A390 gasser that I switched safetys on. Love the gun, easy on the shoulder, shoots all season without cleaning. Unfortunately, my young son sort of "appropriated" it.
I bought an SBEII a number of years ago because I liked the simplicity of the interia system. I killed a lot of waterfowl with that gun, but got tired of the recoil and the FTF too many times to count. So I sold it. (FYI - Benelli just came out with a true LH SBEIII at SHOT this week).
Bought a true lefty Beretta A400 this year. Couldn't be happier. Ran a 100 through it this week at the range, both skeet and trap. Took it to the Todd with 1 9/16 3.5"s, although never fired a round. The kick-off system really does reduce recoil by 70%. Once I dial it in it will be a gun that I will have for a long time.
You don't have to settle for a right hand gun that shoots lefty anymore - although most can have the safetys switched. Beretta makes a good gun in all pricepoints - the 300 can be had for $5-600. I'm sure Rem, Win, Brown, all make some sort of left handed versions, but I don't have much experience with them. Remmi - if you want to travel 20 minutes south and run a box through my 400, feel free to pm me.