IMO I'd go with the 10/22, although they go for $197 without a scope at Walmart here. I'd either go with that, and not worry about the plastic which most of these other guns mentioned are also full of, or I'd look for an older used one which you can easily pick up for a similar price. It's the way to go imo. Out of the box it may not be as accurate as the Marlin 60/795, but it's not far behind, and in every other aspect it's a much better rifle. If you really have to have that little bit extra accuracy the 10/22 can be customized to be much more accurate than it is in stock form. Even in stock form though, they are plenty accurate for almost anything most people do with .22's.
I do own the Savage 64, and it's a fantastic rifle. Accurate out of the box, too. Also, you can add an accutrigger later on if you choose.
I'm pretty sure this is false. I've read many times over that you can't add an accu trigger to a rifle that didn't come with it. Well, not without some serious modification anyway. That being said, you can add aftermarket triggers to them if you find one from a company that makes one.
I'm a big Savage fan, and I like their .22's, better than the Marlin 60's I've used, but I still think the 10/22 is a much much better rifle. Normally I like Savage much better than Ruger, but having used a Mark II with a bull barrel and accu trigger that had been modified and a 10/22, I felt that while the Mark II was slightly more accurate, it wasn't nearly as accurate as I expected, and while it did have an amazing trigger, I didn't really like anything else about the gun nearly as much as the 10/22. I ended up selling the Mark II I had as I just didn't shoot it that often, and when I did, I never really was super impressed by it like I'd expected when I bought it.
To me what ruins the Marlin 60/795, is the built on scope rails. Especially now that they seem to have a problem with cutting them straight which ends up causing a ton of problems with the rings sliding on the scope rails. Even when they are cut straight though, they aren't nearly as strong as I'd like and it's very common for scope rings to slide on them. Why anyone would make this design built onto a rifle is beyond me. This pretty much ruins the whole rifle. The next issue I have is the trigger is absolutely horrible on the ones I've shot. Now, the 10/22 doesn't have anything close to a good trigger from the factory, but they have been better than the Marlin 60's I've shot by far. The next issues is that it's not rare for the feed lips, or other internal parts to get bent in the Marlin 60 that causes constant jamming issues. This isn't a huge deal and can be fixed, but it's just one more thing that takes away from it imo. That being said, and I don't have a ton of experience shooting one, just some as a few friends have them, but they all prefer the 10/22's after having them. Anyway, theirs have all been very accurate, but the other things take away from them. Infact, they are just as accurate as the Mark II I had and more accurate than the 10/22's I've shot, but I mean barely. I'm talking maybe .5" better at 50-60 yards at best. At 100 yards, I didn't see much of a difference. To me that wasn't really enough to matter for a 10/22 and it certainly wasn't worth compromising on the other things to get that extra accuracy.
The Rem 597 isn't even in the same category as the rest of these, and personally, it's no way I'd ever consider it.
For the Mossberg 702 Plinkster, I can't comment too much. I have a buddy that has one and I sighted it in for him. He wanted it sighted in at 15 yards so I didn't shoot it very far. At that range it shot great though. I liked it, and as far as I know he still likes his. It felt cheap and had a crappy trigger, but it was $100. To me I almost think I'd get a used Marlin 60 over this though just as they seem to be better quality. I was actually going to buy one of these about 2 years ago at Walmart as I liked the way it felt and the lady at the sporting goods counter talked me out of it. I know it's odd for Walmart, but this lady actually seems to know what she is talking about most of the time, and I've had many good conversations with her in the past. Anyway, when I wanted to buy this one, she told me she'd sell it to me if I wanted, but that she would much rather not. I asked why, and she told me that every person she had sold one too had come back complaining about issues with it. She told me that she recommended the Ruger 10/22, or something else. I can't remember what the other one she was recommending was, but I think it might have been the Marlin 60. This kind of scared me away enough that I didn't purchase it. Then I looked online and some people loved them, but then I read reviews of others having issue after issue with them. So they really seem to get mixed reviews. I did like my buddies okay though, and that's the only experience I have with them.
I know things like the Marlin and Mossberg are a fair amount cheaper than the 10/22, and they are fine for what they are, but I feel there is a big reason why the 10/22 costs extra and to me it would be worth every penny.