As an iOS software developer, I am often asked whether "we" (a team I'm working with, or someone I'm advising) should avoid using Objective-C and instead use a higher-level or easier-to-learn programming language. In general, my answer is "No". The rest of this post explains why.
A bit of background: Apple provides a development tool called "Xcode" which is what they want developers to use to write iOS apps. Programs are written using a programming language called "Objective-C", which enhances C with Smalltalk-style object-oriented message-passing features. Developers also use a tool called "Interface Builder" to visually lay out user-interface elements. Finally, there is a vast collection of libraries known as the "Cocoa Touch frameworks" which provide the programming interfaces to all the cool stuff that iPhones and iPads can do.
I am not going to defend Objective-C or Xcode. Many iOS developers would like to use other programming languages and tools.
The alternatives to Objective-C and Xcode can be grouped into two categories. One category is the set of tools that allow developers to write their apps in other programming languages, using some sort of bridge to the Cocoa Touch frameworks, which are then compiled down to native code just like Objective-C is. Examples of this category are MonoTouch (for C♯) and RubyMotion (for Ruby).
For most developers, my advice is to stay away from these things. Go ahead and evaluate them, and maybe one of them is a good fit for your particular set of circumstances, but if you don't know that you have a good reason to use them, just bite the bullet and learn Objective-C.
Here's why: Developing a good iOS app requires use of the Cocoa Touch frameworks. Learning how to use those frameworks is what is difficult about iOS development. Learning Objective-C should take a competent programmer only a day or two, but learning the frameworks is a never-ending struggle. Apple's documentation and samples for the frameworks use Objective-C. Most of the third-party libraries and other components you will want to use are in Objective-C. The smart people who answer iOS development questions in online forums use Objective-C.
if you are using another programming language to interface with all this Objective-C stuff, you end up with these little walls you have to hop over a lot. I'd prefer not to build those walls. The RubyMotion review by Matt Aimonetti describes how difficult it can be, especially for beginners.
But when you take this approach, you will end up with a webappish app, not an app that takes advantage of what makes iOS special (or what makes any other platform special). Maybe that's the right solution for you, but you'll have to accept that some users will react by saying "Eww, this feels like a webapp".
The Right Tool for the Job
In general, it's a good idea to use whatever tools and APIs are officially supported by your vendor. If you are doing iOS development, that means you should use Objective-C and Xcode. If you are doing Android development, use Java and Eclipse with the Android Development Toolkit. If you are doing Windows development, use C♯ and Visual Studio. Going with other solutions might have benefits, but whenever you choose an unsupported development environment, you are taking a big risk. At any time, the vendor might make changes to its APIs or toolchain that break all tools you rely upon.
Using the right tool for the job is a good idea. Using anything other than Objective-C to develop iOS apps results in more work and more risk. Just go ahead and learn it. You might even like it.