What do you like best?
The pricing tiers are great, as other providers are requiring expensive fees on domain creation, transfer, or renewals, Namesilo is doing their expertise to keep the price down. It is also great for domain parking, as they provide different themes for the parking page, custom text or slogans you can display, and most importantly, Namesilo can also handle domain transfer via auction/market-selling. Great to have this feature when you have couple of domain unwanted, but want to make them as a profit.
Free WHOIS privacy is their gimmick, however that's a big plus to most of us. We don't need to disclose all or even partial information to the public, makes our profile safer, and away from spam. However me myself keeps the WHOIS profile public, to allow certain transparency for my customer to see and gain their trust. Though this action brings us alot of spammy WHOIS junk mail.
What do you dislike?
The panel is a pain in the ass, as you will find there is A LOT of "managers" inside the system, which can be simplified as some other easy-to-understand names, I guess that's their disadvantage.
No Strip payment is a big minus, but as long as they are accepting PayPal, Credit Cards, BitCoin, Skrill, Dwolla, and also Wired transfers, I am happy with that.
As for the API part, it is a nightmare while Namesilo didn't provide any SDK for developers, made us to count on ourselves. However there is a plenty plugins for billing solutions like Blesta or WHMCS, so reselling is not a problem.
Recommendations to others considering the product
Cheap, easy to use, various tlds with decent renewal price.
What business problems are you solving with the product? What benefits have you realized?
Mainly this would be pricing issue, as we have facing a tons of domains need to be consolidate, while for the long term price is the main issue, NameSilo has gave us a great price tier to maintain our plan. Also the drop-catch feature is great, that way we can plan a long term project without the worry on purchasing domains.