I had a very good result with the 3M repair kit.....I was surprised actually.
I try not to leave cars out of the garage when the landscapers are mowing, but... I got a nice start w/ a few spider cracks at the edge f the swept area on the '72 Rover left windshield. Inspection was due so I figured I'd give the kit a try and deal with a full repair later.
The 3M kit was very good, if a bit fiddly but I was extremely happy with the result. You can still see the small
If the repair is a ways out, I'd give it a shot; buy a good kit, follow the instructions carefully. Make sure the syringe and suction cup are tight and you pull a good vacuum. My hint would be to heat the windshield w/ a hair dryer or similar, seemed to make the resin flow into the cracks a bit better. If mothing else, you learn a new skill.