Dear Members and Mods

a) Which system should I go with and why?
b) Can both connect to a wireless router out-of-the-box?
c) Some of my software is only available for Windows.
d) Are both systems equally reliable?

Dell 23 All-In-One
CPU: i7 up to 3.4ghz
OS:Windows 8.1 64Bit
RAM: 12GB DDR3
GPU: AMD Radeon HD 8690A GDDR5 2GB
HardDrive: 1TB 5400rpm Hybrid
Office Home 2013
McAfee 30-Day
Keyboard Wireless
Mouse Wireless
DW 1705 802.11bgn + BLUETOOTH 4.0, 2.4 GHz, 1x1
4 Year Basic In-Home Support

iMac 21.5
CPU: i7 up to 3.9ghz
OS: Mavericks
RAM: 16gb DDR3
GPU: NVIDIA GeForce GT 750M 1GB
HardDrive: 1tb 5400rpm
Office for Mac Home 2011
Apple Mouse
Apple Keyboard with Number Keypad
AppleCare Protection Plan 3year

 If you have the money, go for the MAC.
b) Yes
c) Then you will need to get the Dell or budget AROUND $100 more for a copy of Windows on the Mac (or find alternative software)
d) Very hard to judge reliability, both should be fine though.

There is no real best system out of those, it all comes down to whether you want to use Mac OS or Windows.Several different methods are available for running Windows on Intel Macs:
    To dual-boot between OS X and Windows, use Apple's Boot Camp. ...
    To run Windows in a virtual machine within OS X, use Parallels Desktop, VMware Fusion, or VirtualBox.

Reference: http://www.pcmag.com/article2/0,2817,2344661,00.asp
3 thoughts...

1) All-in-one PC's are junk...very LIMITED on upgradibility...

2)You need to decide between Win and Mac and forget the advice above...even though it does work it's a mess...

3) You need to TAKE your budget into consideration here...