Mining Cruisers are generally the best ships for mining of that particular race. The Osprey and Scythe have gigantic mining bonuses and mine at a faster rate than the others though. The Gallente and Amarr don't have a cruiser with a mining bonus, but in the Amarr's case, an arbitrator with a fleet of mining drones and mining lasers can get 337.5 ou/m from it's drones alone. While the base ore unit carried by a mining drone isn't enough for rarer 0.0 ores such as Arkanor and Bistot, the mining drone bonus provided by an Arbitrator or Vexor gives them enough carrying space.