Is an iisreset necessary or mandatory for a solution deployment, will recycling the app pool do the same thing – SharePoint 2010?

Hi All,

I have a client with a two server farm with 5 web apps owned by different divisions, they have asked me to try and explain solution deployment and IISrests as solution deployments by one division  causes an iisrest and hence SharePoint down time for the other four. I have read article 1 below that explains recycling the App Pools and it mentions in most cases this is enough and also that this doesn't cause downtime - Is this true, does anyone have an answer for this.

Article 1)

http://fullsocrates.wordpress.com/2012/07/25/iisreset-vs-recycling-application-pools/   

In the forum discussion below it mentioned that when using PowerShell to deploy solutions that this method doesn't schedule either iis resets or recycling and that recycling doen't cause downtime, is this correct. Can anyone provide a recommendation for the above?

Forum Discussion 1)

http://social.msdn.microsoft.com/Forums/eu/sharepoint2010general/thread/52fef63c-2e1b-45d8-a961-5f7592025ab3

Thanks in advance,