I actually have two models, one at home and one at work. I use the one at work most often. At work I have the model B-31 or the Mini-Plus, no water pump on this model so that is a HUGE bonus, as the water pumps are the first things to malfunction on most Keurig machines and therefore the # 1 complaint people have about their Keurig machines.
At home I have the discontinued B40. That one does have a water pump but so far it has lasted 2-3 years. If you do buy an Eko-Brew filter, read the instructions. I had Starbucks grind me two bags of coffee and told them it was for a Keurig machine and the coffee has been weak, with a lot of sediment on the bottom. So when I go back there today to buy another bag, I am going to tell them to grind the bag on setting # 8 which is what Eko-Brew recommends on the videos at their website.
They also say if you buy your coffee at the grocery store, already ground, it should be fine as is. I have been thinking about grinding my own coffee and am thinking about getting the Kyocera Manual Ceramic Burr grinder. It costs $50 I think and looks like about all I need, right now. I love the Eko-Brew filter because it allows me to drink coffees I like that Keurig doesn't carry and with the price hike I just can't justify that kind of money for such mediocre coffee.