Hey Juan!
When speaking with a lender, your rate and fees are always important but beyond that more importantly you may want to ask people you know for references. The investment world is definitely a different niche, so finding an investor friendly lender is huge. Here on BP is a huge resource and although I'm not part of the Lender Finder, you would probably have good luck there or in the forums. Check for their online presence and reputation. If a lender doesn't show up online and has poor reviews, the listing agent for your property will find the same thing when you submit an offer with their preapproval letter. For the lender, it's important to know whether they broker your loan or lend in-house and understanding the pros and cons to both. Brokers may have more flexibility and options for your loan whereas a direct lender will only have their own products. On the other hand, brokers act as a middle-man in the transaction and take a fee for it, so you may find that a broker would have higher fees than the direct lender. Brokers also may have less control over the timeline and structure of the process, since you are not utilizing their underwriters/closers in most cases. Again, pros and cons to both and so you may benefit from speaking with both and weighing the options they offer.