<p>Currently I am using NetTiers to generate my data access layer and service layer. I have been using NetTiers for over 2 years and have found it to be very useful. At some point I need to look at LINQ so my questions are...</p>

<ol>
<li>Has anyone else gone from NetTiers to LINQ To SQL?</li>
<li>Was this switch over a good or bad thing?</li>
<li>Is there anything that I should be aware of?</li>
<li>Would you recommend this switch?</li>
</ol>

<p>Basically I would welcome any thoughts
.</p>

NetTiers is very good for generating a heavy and robust DAL, and we use it internally for core libraries and frameworks.
As I see it, LINQ (in all its incarnations, but specifically as I think you're asking to SQL) is fantastic for quick data access, and we generally use it for more agile cases.
Both technologies are quite inflexible to change without regeneration of the code or dbml layer.
That being said, used properly LINQ 2 SQL is quite a robust solution, and you might even start using it for future development due to it's ease of use, but I wouldn't throw away your current DAL for it - if it aint broke ...