Default Buy SGS4 now or wait for S5 in April??

I've been researching the two devices but could still use advice. Here's what I've come up with so far:

SGS4
5.4 x 2.7 x 0.30 inches
4.6 ounces
Android 4.2 (Jelly Bean)
up to 15.5 hours talk time
up to 18 days standby time
13MP Camera with 1080p HD Recording
2GB RAM, 16GB ROM
Sync methods: Bluetooth, WiFi, USB, NFC
4G Capable
Wi-Fi Calling
Audio and Multimedia
T-Mobile TV
GPS and Apps
GPS enabled
International
UMTS: Band I (2100);UMTS/HSPA+: AWS Band IV / 2100 / 1900 / 850;Band II (1900);Quad Band GSM;LTE
Hearing Aid Compatibility
M3

Size and Weight
5.59 x 2.85 x 0.32 inches
5.11 ounces
Android 4.4.2 (Kit Kat)
2.5GHz Quad core application processor
16 MP Camera
2GB RAM, 16GB ROM, 128GB Expandable Memory Slot
Sync methods: Bluetooth, WiFi, USB,LTE
4G Capable
4G LTE Capable
Wi-Fi and Mobile Calling
T-Mobile TV
GPS and Apps
GPS enabled
International
UMTS: Band V (850);UMTS/HSPA+: AWS Band IV / 2100 / 1900 / 850;Band II (1900);Quad Band GSM;LTE

Looks like the big differences are the processor (is it same just overclocked or new hardware?), the camera (+ 3MP), heartrate sensor.
Does the S4 also have the expandable memory slot and dual wifi/4g data transfer? I want a phone I can root but I don't want to invest in something that will be quickly outdated...