This depends on what you want to do and what year car you are planning to purchase.
The early Monte Carlos are easy to work on the ones with rear wheel drive.
I have owned a 70-72 and an 85 Monte Carlo. I currently have a 99 and it isn't to bad I had a 96 that my son drove and that got me a lot of experience on the 5th Gen.
Seems like the 6th & 7th gen's on this blog have a huge array of issues. But if you buy as a second owner and get a car with 60K or less on it you should be good.
Do a good test drive before you buy it.
If you buy parts get original replacement parts and not aftermarket from Amazon, seems like the guys have a bunch of issues with that for some reason.
The one thing I have learned with what I have read is don't replace the Radio in these cars all the settings and resetting go thru the radio and if you cut those wires you are going to have some serious issues.
I would say if you want to customize the sound system find another place to put it in the car. I am sure there are other tips that can be mentioned however I will let some one else bring those to light