Another vote for the Can-am.  I've had mine for several trouble-free years now, with over 3000 miles on it.  Since you stated one with 4wd "for the hills" I'm assuming you want one that's more trail-oriented than work-oriented.  The Kawasaki Mule you mentioned is work oriented, as are the Kubota units.  They don't have the articulation, the suspension to compete with a trail-oriented machine.  But good luck finding one in your stated price range....like everything else, the price has gone way up in the past 3 years.  A current Can-am like mine has gone up by $10,000.  And as for those advocating a Jeep instead of a side by side...I own both; I've been a Jeep Wrangler owner most of my life and still own a 2006 Rubicon.  Yes, the Jeeps are nice machines.  But a 100 mile ride over a rough trail in a Jeep will leave you feel like you've been pounded by a bat.  That same ride on a side by side, with the soft independent suspension, is a piece of cake.
My Can-am on the mountain behind my house this past summer:
	
		
			
		
		
	
		
			
		
		 
	
	
		
			
		
		
	
On a trail ride with a Yamaha Wolverine and a Honda Pioneer:
	
		
			
		
		
	
		
			
		
		 
	
	
		
			
		
		
	
								My Can-am on the mountain behind my house this past summer:
On a trail ride with a Yamaha Wolverine and a Honda Pioneer:
 
				 
				
		 
 
		 
 
		 
 
		 
 
		
 
 
		 
 
		 
 
		