[squid-users] Transparent Vs Non-transparent proxy

Hi,

I need an expert opinion on best suitable setup for my requirement. I am
running shorewall 4.4 on RHEL 5 for NATTING/FIREWALLING. I've installed
SQUID-3.0STABLE20-1 on that same machine as well. Shorewall is
REDIREC-ing port 80 traffic to squid. Currently Squid was running in
transparent mode until I found that almost all users were having very
frequent breaks in internet. I configured client browsers with
squid-server address as http proxy with port squid was running on. This
worked and internet problem solved.
My question is that is that a common problem with squid running in
transparent mode with shorewall?
When I've configured client browsers with http proxy address, now it is
no more a transparent proxy, is it? so should i change it to
non-transparent mode?
What is the main advantage / drawback of running squid in
transparent/non-transparent mode?

Any insight here or through any article on internet is well appriciated!

-- 
Regards,
Asim Ahmed Khan