Here is First Majestic's store for buying silver bullion:
And Great Panther's:
I think these are probably quite good options. The minting quality will be fine and the recognition value will be high. There shouldn't be any liquidity problems.
Post up other experiences of buying directly from miners or links to their online stores.
I have purchased many times from first majestic and have found they have had an interesting premium on their bullion. Sometimes you can buy their stock with as little as a 3% premium depending on the general market direction of silver, as it goes up their website doesn't update the price quickly at all. Comparing their prices to Border Gold shows why, they get their data from Border Gold and adjust prices accordingly. Now, if you are looking for "Recognized" silver then BG is the place to go, as I am unaware if FM silver is considered to be "Recognized", but the prices correspond to this market, and not the unrecognized bullion.
Shipping was always good, but again in the last 8 months there has been some delays in the shipping, primarily due to the strong demand and limited production capacity from Northwest Territorial Mint. The boxes my items were shipped in were bubble packed, and the boxes tend to be well sealed making it difficult to open. Shipping prices generally have cost me around $35 dollars per order since I do not live in the Vancouver Metro Area, otherwise it would likely be $25 or so.
Most of the time I have used a credit card to order with just for convenience. All new accounts must provide proof of an address using a utility bill or other item with your address. I was told this way it prevents stolen credit cards from being used on the purchases.