If you HAVE to make this choice, Eqvalan. Panacur EG is a benzimidazole wormer and there are high levels of resistance to it in many areas. The best thing to do would be to have a worm egg count done (by your vet or someone like Westgate) and then worm accordingly. The count won't test for tapeworm though and you can either have the vet take a blood sample and send this away to be tested (which is expensive), or worm for tapeworm 'blind'.
I've just wormed mine with a double dose of pyrantel (the wormer was Exodus, which is the cheapest I can find) - I worm once per year for tapeworm and two of them had moderate redworm burdens too, so this covers everything for them. The only thing it doesn't do is bots - you do need an ivermectin wormer for them, but they are not particularly dangerous.
5 day guard is best for horses who haven't been done for a while or you don't know the're worming history. It's kills the worms over the course whereas if it has got a high worm burden and you kill them all in one go with a stronger wormer you run a high risk of colic with them all coming out at once