We recently received a note from a reader who's isn't impressed with the current lineup of smartphones, and who longs for his venerable Palm T/X PDA. Matt believes that in the rush to create the slimmest and sexiest smartphones and tablets, companies have forgotten that some of us look for features other than the sharpest display or fastest processor. Matt writes:

While I'd like to get a smartphone or tablet, I'd like to improve on my 08 Palm T/X. It starts instantly, has a great calender/day planner, a fair amount of lower tech apps, Bluetooth/Wi-Fi and runs up to 25 days without a recharge...with it's original battery. Which smartphone has half that? It seems like we're moving backward to move forward, or maybe we're not moving at all?

While there are many smartphones and tablets that offer some of these features, finding one that has it all will be tricky -- especially one with a standby time of 25 days. But we are on the case.

For Matt, it looks like the most important features of a handheld device are its boot time, calendar, app selection and battery life. Unfortunately, mobile devices today take a fair amount of time to launch. The iPhone 4S, for instance, boots up in 35 seconds, while the Droid RAZR Maxx takes about 50 seconds. The iPad 2 takes less time to boot up -- just 18 seconds, but that's hardly instantaneous. In truth, it's hard to find an "instant-on" device these days.

Both Android and iOS feature robust built-in calendar apps that allow you to create events on an hourly basis for every day of the week, establish start and end times, set reminders and create a repeating schedule (daily, weekly, monthly and yearly). Android phones also offer users the ability to sync their phone calendar with their calender in Gmail, as well as include people on their contact list in an event (which sends a notice and reminder to all those included).

If the built-in calendars on Android or iOS devices don't do it for you, there are a large number of free and paid calendar apps available through the Apple App Store and Android Market. On the Android, "Touch Calendar" allows you to zoom into and out of your calendar like a map, making it easy to move from day to day without having to navigate between the tabs for day, week and month. "Week Calendar" on the iPhone fills a gap in the built-in iOS calendar app -- a lack of a weekly view. The app also includes views for month, day and list as well.

When it comes to selection of apps, the iPhone and iPad are hard to beat. The iPod Touch might also be a viable alternative to the smartphone world, which still offers the app selection Matt wants. The Apple App Store boast a huge selection of apps (more than 500,000), and although the Android Market has grown remarkably since it was first launched -- from a few hundred apps to well over 200,000 -- it still can't compete with the sheer quantity of apps available on the Apple App Store.

Unfortunately, it doesn't look like any smartphone or tablet currently on the market can compete with the battery life of Mike's Palm T/X. Without a doubt, battery life is the major shortcoming of today's mobile devices. The iPod Touch is rated for 40 hours of audio playback and 7 hours of video playback, but that doesn't exactly cut it.

Some phones are better than others. On the LAPTOP Battery Test (continuous surfing over Wi-Fi), the average smartphone lasts only 5 hours and 41 minutes. Among 4G phones, the longest-lasting is easily the Motorola Droid RAZR Maxx, which lasted 8 hours and 25 minutes on the LAPTOP Battery Test. (We even managed to eke out more than 10 hours of battery life using 10 battery-saving tips.) According to Motorola, the RAZR Maxx features up to 380 hours (15.8 days) on Standby before needing a charge -- not quite the 25 days that Matt got with his Palm T/X, but long-lasting nonetheless. A number of other phones, such as the Samsung Galaxy S II and T-Mobile Sidekick 4G, offer long battery life as well.

So in today's world where PDAs are a thing of the past, Matt's not going to find everything he wants; particularly when it comes to battery life and boot time. However, now handheld devices do so much more that the compromises can definitely be worth the tradeoffs. For our money, we'd recommend the Droid RAZR Maxx or the Apple iPod Touch to meet Matt's needs.