look at the key security company websites at their reports on Android, each release exploses another flaw (Gingerbread exposed a keylogging flaw that was sinple to exploit) this coupled with an totally open and uncontrolled marketplace just makes it a minefield
As does EVERY OS release, by ANY company. Look at Lion

You not seen the bugs each iOS release brings?

The Market place does need more control, but it's Google's ethos of being open that's keeping the way it is, thus the Amazon Marketplace and carrier Market's/stores where there is more control. But at the same time each app you install will tell you what permissions it needs, if it's a simple game and wants access to your Phone calls, record calls, place calls, Text messages etc don't install it, 'tis not hard. If the app has a new version and you upgrade it will tell you if the permissions have changed, even for the Apps you've set to autoupdate.
Also one big issue is that each manufacturer adds their own spin to each release and on top of that each carrier adds their own personal requirements... so when you say I have Android 2.3.4 on a Samsung device from Orange.. this wont be the same as 2.3.4 on an HTC from Vodafone - each version will use a different kernal and other aspects will be different - let me give another example, the native email client and PIM services on a 2.3.3 Galaxy tab from Vodafone UK wont connect to ActiveSync 2010 (there is a know bug with SSL) but take the same tab from AT&T in the US and it will work fine...
That's a Samsung issue and should have been addressed before releasing the effected devices, it also effects the SGS2 - 2010 has been around long enough now. My old HTC works fine with Exchange 2010, prompts me to accept the permissions the server needs to control my phone and off I go.
This is where is have to concede Apple have the upper hand.. complete control over OS and HW means that 4.2 from one carrier = 4.2 from anther carrier globally no discussion
This complete inconsistancy is the reason why banks will stay away from Android for sometime yet.. there are too many unknowns
It's also their limitation as they only release 1 iphone and 1 ipad a year (currently), variety and choice is what makes Android and WP7 good.
Banks are staying away from Android because of the FUD being spread, what's wrong with an App that's effectively an interface to the webpage (which they already provide if you do to the mobile banking website for Lloyds and Barclays), sending data over SSL/TLS (using the versions that are not effected by the recently possible security issue with those protocols). Plenty of other apps function that way without any security issues. It's mostly FUD being spread by those who do not know what they are talking about is the issue.
Even if that were the case it still took the banks years to react to the iPhone and come out with Apps.
Just had a look and it appears Lloyds and Barclays don't even have an iPhone/iPad app, so even if I did have one of them fruity tooty tings I couldn't 'micro manage' my money anyway without using the mobile banking website
How many UK banks actually have an iphone/ipad app? Natwest and... ?

I don't have itunes so can't check even if I wanted too.