[plt-scheme] Relational Database options

Hi,

I was wondering what options I have for building a database backed
website on PLT-Scheme.

So I went searching - these are my results.

SrPersist;  Requires a ODBC driver manager - not currntly maintained
> Eli Barzilay  to Jaime, PLT 5/9/08  [The code in the PLT tree is not maintained.  If there's anyone that can revive it, please let me know.]
http://www.plt-scheme.org/software/srpersist/

sqlid.plt contributed by oesterholt
supports (as an extra download) sqlite and postgresql (MySQL driver in
development)
http://planet.plt-scheme.org/display.ss?package=sqlid.plt&owner=oesterholt

spgsql: PostgreSQL connectivity
for connecting to a PostgreSQL database server over TCP.
no dependencies
http://planet.plt-scheme.org/display.ss?package=spgsql.plt&owner=schematics

SQLite: An interface to SQLite databases
- I get the impression that file-lockin would make using this a
problem if the database was getting a bit of traffic.
http://planet.plt-scheme.org/display.ss?package=sqlite.plt&owner=jaymccarthy

mysql - only one;  Geoffrey S. Knauth updated David Van Horn's mysqlclient.
http://knauth.org/plt/mysql/
see thread http://groups.google.com/group/plt-scheme/browse_thread/thread/f102c7f1daa1f69b?pli=1
-or- http://tinyurl.com/b2mflh

Who uses these and what for?

What db does Planet use?

What would you use for a database backed web site?

TIA,

Stephen