According to specs the 2nd gen. Moto G has network support for: GSM/GPRS/EDGE (850, 900, 1800, 1900 MHz) UMTS/HSPA+ up to 21 Mbps (850, 1700 (AWS), 1900 MHz)
What's the actual maximum upload speed?
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According to Wikipedia: High Speed Packet Access and Evolved HPSA, HSPA+ has a theoretical maximum download of 84 Mbps and an upload of 10.8 Mbps. Using Dual Cell Technology, it can be doubled to 168 Mbps download and 22 Mbps upload.
This suggests that the upload speed will not be anywhere close to the download speed. Doing a search for HSPA+ 21 Mbps, most results show 3G USB devices with a max upload of about 5.7 Mbps.
GSMArena also lists the Moto G (2014) as having an HSUPA of 5.76 Mbps.