Stig, I have a Noco 1000A jump starter and also a no name Chinese one (~$30). The Noco lives in the car my daughter will hopefully, someday be driving on her own!
I have only used the Noco once but it worked fine. I remember to recharge it about once or twice each year and it seems to keep at least 90% of its charge in between.
I also like the idea of using it to jump start a bike in the garage, if needed. (haven't needed to, yet). Easier and much safer than jumper cables from a car.
Project Farm (youtube) has done a big test on these. 'Bob Is The Oil Guy' forum has a huge thread on these.
They work well, are very convenient, safe and you don't need to rely on a stranger for help, if needed. (or do a belt and suspenders approach, keep them both in your car!)
edit: I just noticed in the Amazon listing where 30,000+ were purchased in the last month alone..I think they are pretty popular
edit #2: attached pic of other one I own. Purchased due to good reviews and dirt cheap price (maybe $29 at the time?). Haven't used it, yet. Disappointed in that I think my cell phone weighs more than this thing does. The Noco is solid and heavy. This thing is a featherweight and feels like a toy.
