В принципе, по дальности обещали не хуже, а лучше GPRS'а. Взято по ссылке: https://arxiv.org/pdf/1802.04222.pdf
The downlink of NB-IoT is based on OFDMA, with 15kHz subcarrier  spacing,  and  reuses  the  same  OFDM  numerology as  LTE.  Both  single-tone  and  multi-tone  are  supported in  the  uplink.  Multi-tone  is  based  on  SC-FDMA  with  15kHz subcarrier spacing. With single-tone, sub-carrier spacing can be 15kHz  or  3.75kHz.  NB-IoT  achieves  a  20  dB  improvement over GPRS, giving a maximum coupling loss of 164dB.