It depends on what you need. £10 lights will be better than a set from a pound shop by a long way, but I don't believe £100 lights would be 10 times better. The laws of diminishing returns kicks in my opinion.
On my Peugeot, I have a Basta Quattro bottle dynamo, ~£10, a B & M Lumotec halogen headlamp, ~£20 new (I bought mine for £3 second hand on ebay), a Soubitez tailamp with standlight (run of a battery rather than a capacitor like more modern designs but battery lasts for years), ~£5. It is sufficient for my needs, I have done my own visibility tests and it's perfectly visible and it costs nothing to run, drag is minimal from the dynamo. I happily ride at 20mph on unlit roads with this with no problems, it wasn't that expensive at all and it should last for years with no running costs apart from an occasional bulb. As the lights are physically bolted to the bike, they won't fall off or get pinched if I leave the bike outside a shop. Personally, I would never consider battery lights ever again.
On my Peugeot, I have a Basta Quattro bottle dynamo, ~£10, a B & M Lumotec halogen headlamp, ~£20 new (I bought mine for £3 second hand on ebay), a Soubitez tailamp with standlight (run of a battery rather than a capacitor like more modern designs but battery lasts for years), ~£5. It is sufficient for my needs, I have done my own visibility tests and it's perfectly visible and it costs nothing to run, drag is minimal from the dynamo. I happily ride at 20mph on unlit roads with this with no problems, it wasn't that expensive at all and it should last for years with no running costs apart from an occasional bulb. As the lights are physically bolted to the bike, they won't fall off or get pinched if I leave the bike outside a shop. Personally, I would never consider battery lights ever again.