I had an 05 Frontier and loved it. It was a great truck and if I was in the market for a mid-size, I'd go back in a heartbeat. With that said however, I traded it in on a 2011 GMC Sierra (needed more space). I like it a lot better. Not only does it have more power (seems obvious given the V8, put the Nissan 4.0L is a VERY powerful little V6), but it gets better fuel economy.

So to answer your question, if I specifically wanted a mid-size, yes, I'd recommend the Frontier. If that isn't that big of a deal, I'd consider other options.