I would stay away from any Volvo Penta for the reasons mentioned above, especially if you can not do any of your own maintenance. I as well was mechanically declined. I did know "righty tighty, lefty loosy" and that's about it. I watched someone winterize their boat and was amazed how simple it was. I was paying someone 100 bucks, CDN as well to do it for me. Over that winter I took a small engine course at Mohawk College in Hamilton. The best money and time I spent in years. I won't tear apart an O/B but now understand the basics and have assisted tearing a marine engine apart and putting them back together though. . I now do my own "simple" maintenance and have saved hundreds in Marine mechanic charges. It's going for around $120.00 an hour here. If you are dead set on a I/O then that's what you should buy but again I would only go with a Merc. I/O and outdrive. It's your basic 4 or 6 cylinder GM car engine. But now you're dealing with rubber boots, bellows, tranny linkage, gimbal and all that goes with an I/O. It will get expensive and that is a guarantee if you have to pay for all maintenance. You can't be much less mechanically inclined than I. You Tube and sites like iboats are your friend. Don't quit before you try is my best advise. However if you have hands the size of Shaquille O'Neal's well then be prepared to pay someone and forget the DIY.
As for the quality of a Glastron vs. others from what I have seen where we putter around with boats at a pals shop they are indeed an entry level glass boat with I/O but will do what you need it to do. Always go for the larger size engine and length your budget can withstand, always. It might be a good idea to put at least an electric trolling motor on whatever you do buy, it will save you a 26KM paddle, mine did for me once.