Hi,
I have just returned from the Amritsar add-on so can provide a bit more detail for those considering this.
Day 1 - train from Delhi to Amritsar (takes approximately 6 1/2 hours), had lunch in hotel around 7pm before leaving at 8:30 for visit to Golden Temple with guide for evening ceremony and visit inside the temple (our guide was very informative and managed to get us a great view and got us into the temple).
Day 2 - left hotel at 10am for daytime visit to Golden Temple (looks different than at night so well worth going back). We had the same guide all day and we had a very informative visit round the kitchens which feed thousands daily. We then visited Jallianwal Bagh, which was very thought provoking, before having lunch (at our expense) in a nearby restaurant. After lunch, we went to the Indian/Pakistan border for the Wagah Bagh border ceremony, before visiting Durigiana Temple on way back to the hotel for dinner.
Day 3 - left hotel at 12 for internal flight back to Delhi.
I think the cost was well worth it just for seeing the Golden Temple - twice, not to mention all the other places we visited, and the extra 3 nights hotel stay (including breakfast and evening meals), tour guides/coach driver, train journey, and internal flight.
I agree JY could perhaps put a bit more detail into their description of the add-on as it is a bit vague and doesn't mention some places we visited. It would be a shame to miss out as I loved the Golden Temple.
I hope you will find the above useful when deciding whether to do the add-on.
Regards
Caroline