Cold booting my 7 MHz A600 to a fully loaded, functional and responsive desktop takes 17 seconds from hard drive (I just measured). Pretty decent, I'd say.
There's plenty about Amiga that is and/or feels instant. My workhorse is a 14 MHz A1200 and I use it at least once a week, so I get plenty of opportunity to compare. For its intended use cases, most things feel very snappy. Then there are of course areas where it doesn't stand a chance compared to a modern PC, even if the workload is "Amiga sized". Decompression and picture downsampling, for example.
There's plenty about Amiga that is and/or feels instant. My workhorse is a 14 MHz A1200 and I use it at least once a week, so I get plenty of opportunity to compare. For its intended use cases, most things feel very snappy. Then there are of course areas where it doesn't stand a chance compared to a modern PC, even if the workload is "Amiga sized". Decompression and picture downsampling, for example.