Are there good and bad domain registrars
 

I purchased my .au domain several years ago through a discount reseller when I first started my business. As my domain is again due to be renewed I was wondering if there is much difference between all the available domain registrars and resellers. Changes of ownership and management of HOSTING companies is obviously a big deal and this site provides regular updates in this area, but do the same issues need to be taken into account when renewing domain ownership through resellers etc?

What issues or concerns are there when buying or renewing a domain name and how do you make sure your domain is safe and futureproof if your reseller becomes "unstable" or "dodgy" ?