Help picking a free CRM system.

Help picking a free CRM system.

My eyes are glassing over a bit (total novice here), but I am looking at the free CRM versions: ZOHO, Capsule CRM, and Really Simple Systems. I have a very small business that I am looking to manage info on leads for possible new accounts. We only need two users (myself and my wife). Having no experience with a CRM, I'm not sure of any possible limiting factors of the basic free systems mentioned. 
The basic criteria I have on the above are:

ZOHO:  Users 3,   Storage 100MB,   Accounts ? (I did see this listed),   Contacts ? (I did not see this listed)

Really Simple Systems:  Users 2,   Storage 100MB,    Accounts 100,  Contacts unlimited
100 accounts sounds like a lot for us, but if we hit the limit, would it be easy to download all the data to my computer (so I can save the leads of questionable value), then delete these marginal leads on the cloud to make space for more there?

CapsuleCRM: Users 2,   Storage 10MB,    Accounts ? (I did see this listed),     Contacts 250
Says iPhone compatible. We both have iPhones. Any idea if ZOHO and/or RSS are iPhone compatible too? 


Basically, I'd like to know: (I am trying to upgrade from using an Excel spreadsheet)
1) The # of accounts and contacts the free ZOHO allows? 
2) Is 10MB of storage (Capsule) best to pass up in lieu of 100MB even for a small user?
3) What basic features might make one system more useful than another. Not knowing how I would use it limits your (and my ;o) ability to give specific answers, but I am hoping that there may be some general thoughts that may help me with a decision. Your guesses are likely more informed than mine.  ;o)

Our systems (if it makes any difference): 
I use a Mac with Entourage for email (I bet this negates my using email with and CRM).
My wife uses Windows XP ver. 2002 SP3 & Outlook on her home laptop (probably newer OS at her work) 

Than you in advance for any insights.
Dave