Like a lot of other things, "it all depends." How serious are you about the hobby? If you have the dreaded Machine Cookoo virus for which there is no known cure, ensuring that you will forever be plagued with an uncontrollable urge to build things using lathes and milling machines and whatever other machines you can cram into your shop, I'd suggest you spend more money and get a knee mill like the G3102
http://www.grizzly.com/products/Vertical-Mill/G3102. If you are in the advanced stages of the disease, look at the G0695
http://www.grizzly.com/products/VS-Milling-Machine-with-Ram-Head/G0695
Now, they are two or three times the price of the ones you're looking at so it may not be feasible, but give it thought. If you look at it as a lifelong investment with the cost spread over 20 or more years of enjoyable use, the cost may look a bit less daunting. For instance, if you take the $2,695 cost of the G3102 and divide by 20 years, it works out to $184.75 a year. Not so bad. The problem of course is coming up with the total $2695 up front.
If you just testing the waters of machining, to see if you like it or not, then a small machine like the G0619 may suit you fine.
It also depends on what you are going to make. Ignoring for a moment the Rule of Milling Machines that says the table on a milling machine is never big enough, assume everything you are ever going to want to do will be "small" and reasonably within the capacity of the G0619, there may be little point in getting anything bigger. I suspect you will discover, however, that the Rule of Milling Machines applies in your case as well, and projects will come along for which the G0619 will be inconveniently small.
Whatever you get will be better than no milling machine at all.
So...I'm not sure that tells you anything definite, but it may give you some things to think about as you decide.