This is a horrible question. It lacks definition on every front. Mass immigration, controlled, limited immigration, or controlled selective immigration? With or without welfare? What kind of welfare? With or without integration programs? What kind of programs?
All those change the answer greatly. If there's no welfare, and no integration programs, there will never be mass immigration. Those who will come, will struggle, those that will stay, will usually be a great economic benefit, and the ones who don't manage, will self deport. With a little support, and some integration programs, more people will come, and more will stick around, but those extras will not be as good as those who'd stick without support. Still, overall economical plus, and still not a lot of immigrants. On the other hand if you provide extensive integration programs such as different languages in school, as well as lots of welfare.. Immigrants will pour in, and in most cases, just for the money. They will usually not integrate as well. This is a pure economical loss, as well as a dangerous, and bad overall idea - you are destabilizing your country's ethnic, economic, and moral balance, ensuring big problems, and surefire unsustainability and disintegration in the long run.
Immigration can easily be seen as a economic incentive to any particular country.Immigrants normally bring in skills that domestic workers may not have.They also perform jobs that local workers may see as distasteful or demeaning therefore getting jobs done in industries such as farming that might otherwise not be completed.
Immigration has both its positive and negative implications here in our country. But for the most part I believe that immigration in general has more negative risks then positives. Immigration creates a large strain on our economy and it will only get worse if we do not cut immigration spending where we can.