As others have stated the two should not be compared. If there was to be an article written it should be titled "Entering JATC with or without Line School credit." Attending line school is a great way to get your foot in the door and obtain an apprenticeship. IN NO WAY SHAPE OR FORM SHOULD LINE SCHOOL EVER BE A REPLACEMENT FOR JATC. Although, some line schools cater to non-union outfits and turn out students to go work as a "lineman" at their company with only line school experience. This is not right, it's dangerous and should not even be an option. But, directors of these line school programs are looking at job placement numbers for recruitment purposes and need those numbers to sell their program.
I'm happy that you are taking it upon yourself to get into shape to be ready for an apprenticeship. No one wants to hire a slug. My advice is if you are in a position that you can sacrifice some time to attend line school you should definately do that. While attending school, contact the utilities/contractors/apprenticeship programs to get your name out there find out what they are looking for in an "intern" or apprentice candidate. Whatever they are looking for...perfect it. Then you will shine when it comes time to tryout or bid for a spot.