When Microsoft's Lumia 640 and 640 XL were introduced at the Mobile World Congress earlier this month, many excited fans were surprised to hear that the new phones were coming out so soon in April, but with availability exclusive to At&T and T-Mobile networks, many are also feeling that there aren't enough options.

The 5-inch Lumia 640 is a budget-savvy smartphone from Microsoft that features everything you need to have a powerful smartphone, without all the added fluff that the more expensive phones may have. The larger 5.7-inch Lumia 640 XL, once rumored to be called the Lumia 1330, is just more of the same successful formula on a larger screen.

The April release of both phones will feature Dual-SIM and LTE versions with Windows 8.1 loaded standard.

As for technical specs, both phones are almost identical except for that display size, and they both feature the quad-core 1.2 GHz Cortex A7 CPU with the Adreno 305 GPU, 1 GB RAM, 8 GB storage (expandable to 128 through microSD), and a multi-touch screen with Gorilla Glass 3 durability.

The rear camera on the standard 640 is an auto-focus 8-megapixel with a 0.9-megapixel camera in front. On the 640 XL, those cameras are upgraded to a 13-megapixel in back and a 5-megapixel in front. This allows for full 1080p video at 30 frames-per-second. Both phones also feature Bluetooth 4.0, assisted GPS, FM radio, Internet radio, 802.11 b/g/n Wi-Fi, and USB 2.0 connection.

The battery on the 640 XL is also larger at 3,000 mAh, versus 2,500 mAh on the 640 to power that larger display. This means 23.7 hours of talk time on a 3G connection for the 640 XL and up to 39 days of standby time. This is the type of feature that really makes those with the more expensive smartphones green with envy.

"Open the box and power on your Lumia 640 LTE to the full range of free Microsoft services built in and ready to go," Microsoft describes, highlighting the services available standard with the Lumia 640 and 640 XL. "Connect to friends and family with Skype, enjoy instant access to your photos and music on OneDrive, and edit files with Microsoft Office from wherever you are. Balancing your work life and personal life just became easier."

AT&T will be the first to retail both phones, but T-Mobile will not be far behind. Unfortunately for Verizon, Sprint, and U.S. Cellular fans, neither phone will be on those networks. This may be a point of contention for many, but Microsoft believe that it's the best for this budget-minded phone.

The price of the 640 is expected to be around $149 while the 640 XL should be only slightly higher at $200.