Depends on what your goal is for a classic car owner ( all orig, pro touring, strip n strip, cruiser, ect... ). Make yourself a checklist of ultimate wants vs needs for both cars and see which comes closer to your expectation.
The big plus to the 442 is that it has the beefier 8.5 rear w/ 3.73 ratio & 200r4 OD Trans. However if chev power is in your future then your have some work ahead.
Being the Monte is an 84 ( like mine ) you will have the smaller 7.5 rear w/3.42 ratio, 350c lockup trans ( no OD ) and chev powertrain ( making it slightly cheaper to build for more power ). The blue interior / exterior was a 2 year only deal for 83-84 models making them stand out a little. ( mine is white on blue )
My personal preference is I wouldn't own another car with T-tops so neither car you mention would appeal to me.
However after owning and modding my monte for the last 6-7 years; if I were to do it over again I would get a loaded hardtop 442, beef up the 200r4 trans and drop a 403 in place of the 307 and call it a cruiser.