clarify that virtualizarr is a user-level replacement for kerchunk (#192)

Author: TomNicholas

README.md

@@ -4,6 +4,8 @@
 
 VirtualiZarr (pronounced like "virtualize" but more piratey) grew out of [discussions](https://github.com/fsspec/kerchunk/issues/377) on the [kerchunk repository](https://github.com/fsspec/kerchunk), and is an attempt to provide the game-changing power of kerchunk in a zarr-native way, and with a familiar array-like API.
 
+You now have a choice between using VirtualiZarr and Kerchunk: VirtualiZarr provides [almost all the same features](https://virtualizarr.readthedocs.io/en/latest/faq.html#how-do-virtualizarr-and-kerchunk-compare) as Kerchunk.
+
 _Please see the [documentation](https://virtualizarr.readthedocs.io/en/latest/)_
 
 ### Development Status and Roadmap

docs/faq.md

@@ -16,6 +16,8 @@ The above steps would also be performed using the `kerchunk` library alone, but
 
 ## How do VirtualiZarr and Kerchunk compare?
 
+You now have a choice between using VirtualiZarr and Kerchunk: VirtualiZarr provides [almost all the same features](https://virtualizarr.readthedocs.io/en/latest/faq.html#how-do-virtualizarr-and-kerchunk-compare) as Kerchunk.
+
 Users of kerchunk may find the following comparison table useful, which shows which features of kerchunk map on to which features of VirtualiZarr.
 | Component / Feature                                                      | Kerchunk                                                                                                                            | VirtualiZarr                                                                                                                                     |
 | ------------------------------------------------------------------------ | ----------------------------------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------ |

docs/index.md

@@ -4,6 +4,8 @@
 
 VirtualiZarr grew out of [discussions](https://github.com/fsspec/kerchunk/issues/377) on the [kerchunk repository](https://github.com/fsspec/kerchunk), and is an attempt to provide the game-changing power of kerchunk in a zarr-native way, and with a familiar array-like API.
 
+You now have a choice between using VirtualiZarr and Kerchunk: VirtualiZarr provides [almost all the same features](https://virtualizarr.readthedocs.io/en/latest/faq.html#how-do-virtualizarr-and-kerchunk-compare) as Kerchunk.
+
 ## Motivation
 
 The Kerchunk idea solves an incredibly important problem: accessing big archival datasets via a cloud-optimized pattern, but without copying or modifying the original data in any way. This is a win-win-win for users, data engineers, and data providers. Users see fast-opening zarr-compliant stores that work performantly with libraries like xarray and dask, data engineers can provide this speed by adding a lightweight virtualization layer on top of existing data (without having to ask anyone's permission), and data providers don't have to change anything about their legacy files for them to be used in a cloud-optimized way.