This is the best food for guinea pigs. This has less of the harmful filler materials like corn and more of grass with a fiber percentage of 17% which is actually pretty good. This is one of the best brands in UK and I was glad when it was available in India. It's imported by Pet Like That in India and trust me this is really good for your piggies. These pellets are recommended by Admins of Guinea Pig Advice and Support group on facebook too. All in all an amazing product. I even bought 2 extra packs in case the seller stops importing it. ;) All the other best brands like Oxbow or Small Pet Select are not available in India or are available at exorbitant prices. In their absence this is the best brand that is actually available. I am the first person to review it in India too!
P. S. If you're switching from other food like Boltz, it might happen that the piggies may not eat it initially, but you just have to persist with it. Once they have gotten a taste of it they will love it.
Edit: To all those people who are leaving one star rating because their Guinea Pigs didn't eat it, you have to keep in mind that GPs are very sensitive when it comes to their food and if you suddenly change their pellets they may not like it and won't eat it. This is a part of their defence mechanism because they are prey animals and thus don't prefer any sudden changes in diets. Any change in food/pellets must be done gradually over a period of at least 2 weeks. I hope it helps.