Austria has good coverage in general (even in rural areas). Out of the 3 network providers A1 has the best coverage, followed by T-Mobile Austria and 3 (Drei). Prices are moderate to low.
Note: Austria has quite restricted opening hours for shops (compared with international standards). So it can be a problem to get a SIM card in the evening or at weekends.
Frequency bands are European standard. All providers offer LTE (upgrades).