There is no substitute for square inches when it comes to screens. Some screens are wider than they are tall, but I personally think a portrait format is better for navigation. My gpsmap 60 is very good, but the 45dv is much better. The only advantage with the portables is the ability to use battery power. Other than that the 45 wins out. You pay a considerable premium for battery portability.
Having bundled charts saves a packet. A bit like buying a printer. The machine is virtually free, you just pay for the bundled ink cartridges, or charts in this case.
There iare a number of websites where, if you're so inclined you can get all kinds of charts and maps for free. Not that I condone that kind of thing you understand.
That probably wasn't the answer you were looking for, but at the end of the day, you got to do what's best for you.