Struggling to learn a new language - and, more importantly, a new API - is difficult at the best of time. But without a good IDE with code completion, syntax highlighting, outlining and incremental builds it's practically impossible (certainly once you've been spoiled by a high-quality Java IDE like Eclipse). Vala is a high-level OO language which compiles down to native C: so the advantages of Java/C# (good native types, strong typing and garbage collection) with the speed advantage of C, native bindings and core library integration like DBUS and Gtk+... Perfect for Maemo devices.
After struggling to get Monodevelop 2.0 alpha working on Ubuntu, not getting very far with Valide, I turned back to my favourite IDE - Eclipse - and its embryonic Vala plugin, Valable. A few nights of hacking later and I've added (naive) code complete, incremental building, package support and outline views. Screenshots and more info from here.