I'd buy a used one as there are many for sale out there. They don't hold their value like many high end trap guns do and people seem anxious to part with them. Used trap guns have always been the way to go unless your going to have a new one made to fit you. It's easy to buy a good used P or K gun, shoot it, and if you want to sell it you can recover almost all of your money back. Good luck on your final choice as it's totally up to you in the end.
I have a Summit Limited in 20/28 with 32" barrels.
By far one of my favorite guns (I did buy it used...). I've shot some of my best sporting clays scores with this gun.
I live in PA so I am close enough to the factory that I can drive down for the day. I've never needed it, but their warranty is basically - 'we will do whatever it takes to make the gun right.' For me this has the potential of being done while I wait.
The fit and finish are as good as on any gun I've seen (I run a Beretta DT-10 as my primary gun). More importantly to me is the thought and design that went into the gun.
Unlike most guns made in Europe this was purpose built for the US market - not an afterthought added to a European gun. This makes sense in that the US market accounts for way more guns than the entire European market - so why should we settle for their castoffs?
What Guerini brings to the game is a fully featured trap gun that can be adjusted to fit all but the most difficult body types with the added benefit of a adjustable poi; this coupled with a very, very well made gun that points well and has dynamics of a Perazzi is hard to beat. Add in first class customer care and value pricing it's hard to go wrong with Guerini new or used.
I have a CG unsingle which I put on a PFS and I love it. If you get the combo and you are getting older I suggest the 30 inch barrels. This gun comes with a life time warranty. What is not to love about this gun. Goggle what it costs to get a firing pin in a P gun or the yearly "checkup" of a K gun. Besides you can buy a lot of shells with the money you save.
Mine was a 12ga / 20ga / 28 ga combo and the recurring problem was ejectors. Mostly in sub gauges but 12ga was hit and miss too. Beautiful to look at but frustrating to own... I decided it was a case of you get what you pay for. Again YMMV.
Get the CG. And don't look back, for the money the quality,warrantee and service can't be beat, sure you can spend a lot more, checkout the new prices for a Seitz,Ljutic, Perazzi, k-80 etc.check what a used one is going for you'll see how their resale value is , spend the extra money saved on ammo and practice, practice,practice.
I've had my Summit for three + years now ,ZERO problems, most of my buddies shoot Ljutics,they've have more than their share of problems,ribs, triggers, forearms etc. these are 7-8 K guns, My CG just keeps on ticking.
Seitz are fairly numerous too,the guys don't put a lot of rounds through them though, (when you've got 4,or 5 of them though they don't get a lot of use, beautiful guns, for 14K they'd better be) the choice is yours, hope this helps. I'd buy another CG. In a heartbeat. Breakemall ML.