Which tool for monitorind site speed and reliability?

Can anyone recommend a tool to monitor my site's uptime and speed?

I seem to be experiencing a growing number of delays and errors for my site and yet the web hosting company say that they have no problems. (well they would wouldn't they )

Other websites are quick to load onto my computer and a speed check with my ISP shows everything normal.

 

I have used pingdom.com with success.

 

Thanks. I've signed up for a trial account.

 

Hi,

You should try http://siteuptime.com/

 

siteuptime gave us wrong stats. Pingdom is much better. Hyperspin is another very good name

 

I prefer:
host-tracker.com and hypersin.

Best way is to monitor from 2 different places.

 

I use monitis.com, nice interface and have the ability to run 'internal' checks ie. disk space etc. Can send SMS alerts on the higher packages but do offer a free service as well.