I'm not a novice to cruising having been on at least six other cruises on three other lines (Princess, NCL and Royal). We wanted a quick getaway for our 40th anniversary and we hadn't been to Catalina Island. Carnival was the only option out of LA at the time, so we ignored what people had told us about Carnival and booked the 5 night cruise. Maybe I'm just spoiled by the other lines, but I won't bother with Carnival again.
I gave it an overall 3 star rating because somethings were pretty good and others were quite negative. At best, this was a 3 star vacation. Somethings just went wrong and it wasn't Carnival's fault that it rained all day in Catalina, or that Ensenada is pretty boring. But several things were definitely cruiseline specific.
1) Look at all the fine print before you buy anything, because you never get anything for free. For instance, the soda package will get you warm canned soda over ice in a glass. If you want the mug, you pay separately for it. You will be asked to sign a bar tab for each drink even though it's a zero amount. In contrast, Royal Caribbean had Coke's new Freestyle machines that dispenses the soda into your pre-paid specially coded mugs that came with your soda package.
We had an interior cabin; not sure about the 4A part. The cabin was typical of inside cabins except that it has a fake window with curtains. This seemed to be a problem because it thinned the wall between us and the cabin behind us. We could hear their conversations (which were loud) and the banging on their door.
The shower had confusing handles, but we figured it out. It also had a shower curtain instead of doors.
My BIG COMPLAINT is that there is one, count them, ONE plug in the cabin. Luckily we have experience and brought a three pronged adapter that turned it into three plugs and a USB hub for our devices.
I didn't take an excursion in LA.