Thanks for your comment.
Please bear in mind that no Iranian (despite all the rhetoric from Iran military leaders, which is a normal behavior in any country to boost moral an deter the enemies) is under the delusion to think in a case of all out war between Iran and US, Iran will be the winner. Putting aside the technicality and capabilities of each side, it boils down to this: US is a 360 million strong nation (4.5 time more than that of Iran), with a land area 6 times that of Iran and an economy which is 45 times larger. These are the numbers that eventually define who will win in an actual war.
Imperial Japan made that mistake back in WWII. They were order of magnitude stronger in sea and air when compared to US after the Pearl Harbor attack so they thought they are stronger and they can keep it that way but what they didn't realize is that bigger population, economy and resources can easily translate to superior military might and/or number so just after two years, Japan fell behind because it was not able to replenish its lost units as fast as US could.
Back to Iran VS US case, it is the same situation. We may end up in a similar outcome like that of Veitnam war where in a war of attrition, eventually public pressure forces US to withdraw but at the same time we know we will lose all our infrastructure. Iranian are smart enough not to seek such an outcome even if they are announced winner of the war.
So Iran is never looking for an all out war scenario and its strategy is to make its opponents also think twice before they go down such a path. Iran's strategy is to increase the cost of any attack on Iran to the point that any potential enemy like US or Israel, opt for other means like diplomacy or even sanctions.
Going back to your question about Iran's AD system. I can assure you they are as accurate and deadly as you can get. After watching US previous wars eagerly, Iranians know that if they can ground or at least counter US airforce, then they have already raised the cost of any military option for US enough to prevent any attacks to begin with. Thus, AD has been Iran's top priority since almost 15 years ago. Iran established an independent division in its armed forces for AD, started with investing heavily on Radar design and production and at the same time increasing the range and accuracy of its AD missiles. Bavar 373's capacity are yet to be seen but they are already picking the fruit of their investment in Radars and early warning systems.
Here is a sample of how accurate and effective Iran's radars are. A couple of days ago, Iran's head of AD division announced activation of Iran's Nazir radar which is designed to detect drones, stealth and high flying objects. He said from now on, no drone or spy plane can enter Iran's air space without us knowing. Only a few days after that, Iran warned off a US drone, 20 miles off Iran border that was heading towards Iran from Afghanistan:
This is the screen of radar showing the incoming drone. As you can see all parameters of the object is recognized and displayed.
Here is the source that is in Persian:
http://www.mashreghnews.ir/fa/news/624576/شناساسی-و-اخطار-قرارگاه-پدافند-به-پهپاد-رادارگریز-آمریکایی-سند
Iran says it was a stealth drone probably judging by its RCS. Look at the height of the drone: 137, it can be meters or most probably feet. So the radar was able to find an object as small as a drone flying only 41m (height of a ten story building) in a mountainous area like that of Afghanistan.
Everyone knows that detection and guidance is the toughest part of designing an effective AD missiles system. The above news and similar shows Iran already has been successful in designing potent radars. Designing the missile that can carry the warhead to the target, should be peanuts for a nation that can put satellites in the orbit.