I'd echo everyone else on the kits, you may want to mix and match some items. Allow me to share my experience from ~10 years of handloading from pistol calibres such as .357 magnum up to precise fullbore calibres such as 6.5x47 Lapua.
I bought the RCBS Rockchucker press kit for about £400 10 years ago when I starting reloading, simply because RCBS are a reputable brand and before I was a member of Fullbore UK, so I didn't know any different. Here are the items I've replaced or upgraded from that kit over the past 10 years.
1.) Replaced mechanical scales with RCBS chargemaster lite digital powder dispenser
2.) Replaced loading block with MTM loading blocks
3.) Replaced funnel with MTM universal funnel kit
4.) Replaced lube and pad with imperial sizing wax
5.) Bought a micrometer adjuster for the Uniflow powder hopper
6.) Bought an Inline Fabrication 4" micro riser for the press, along with case kicker, bin holder, ergo roller handle and improved primer ejection system
https://www.sportsmanguncentre.co.uk/rc ... master-kit
Please allow me to elaborate on each of the items above to explain why I've made each change. Please note that this kit does not include any type of case trimming which it sounds like you may already have covered.
1.) The RCBS chargemaster lite is a smaller, more affordable version of the well known Chargemaster powder dispenser. This device has a digital scale coupled with a powder reservoir and powder trickler. You enter a desired charge, and the device will dispense the correct amount of powder. The device can be used as a set of digital scales on it's own if need be. In my experience, this item is best suited for extruded powders such as Vihtavuori N140, Hodgdon Varget etc. This device makes loading quicker so I'd call this a "luxury item", but a solid investmentin the long run nonetheless.
2.) The kit only provided one loading block with only 40 holes with one size. When I bought my kit I was only loading .357 magnum and was loading 50 rounds at a time as that was the size of the MTM ammo boxes. I had to buy replacement loading blocks straight off the bat. The grey MTM universal loading tray has 50 holes on each size and the holes come in a variety of sizes so will fit a load of different calibres. I consider these items to be essential if you intend on loading more than 50 cases in one sitting.
3.) The provided RCBS funnel was OK for .357 magnum but was a bit loose when I wanted to load .223, and would leak powder especially with ball powders like Hodgdon H335 and Ramshot Tac. I bought an MTM universal powder funnel kit as this kit features adapters which can be swapped out to cater for different sizes cases, albeit grouped into a variety of case mouth sizes (e.g. .222, .30). A great purchase which I still use to this day, and I consider these to be an essential item.
4.) The silicon case lube provided in the RBCS kit is just messy and junk, in my opinion. The lube was very difficult to dispense from the bottle, the pad dried out quickly and the lube was very sticky. Worst thing is if you get any dirt or debris on the lube pad you could end up scratching your cases. I replaced this with Imperial Sizing wax offerred by Redding. Costs around £5 for a tin and I've been using the same tin after sizing a few thousand tins. You can simply apply with your fingers. An essential item, but cheap nonetheless.
5.) The Uniflow powder measure is fantastic with ball powders such as Hodgdon H335, Ramshot Tac and Ramshot Big Game. You can get very repeatable throws which check out on the mechanical scales. However, extruded powders such as Hodgdon Varget, Vihtavuori N140 and Reload Swiss RS50 and (to a lesser degree) flake powders such as Alliant Red Dot and Alliant Bullseye can sometimes bind in the hopper giving you some erratic powder charges. The powder measure as provided will have a locking nut along with a screw rod with different numbers on there representing the volume of powder dispensed (cc I believe). Once you have thrown a charge for a desired charge weight with a certain powder (e.g. 40gr when checked on scales) you may notice that the screw rod indicates around 4cc. You write this down and next time you want to throw 40gr with the same powder you would then set the screw back to the same position and verify that it's correct on scales. However, I found this to be a faff since there is a crushing washer between the locking nut and the hopper, so it's dificult to get a reliable point to make the reading. Enter the micrometer adjustement. This device works under the same principle as mentioned above, but you don't have any locking nuts in the way. The adjustment is much finer and makes for a more precise recording. Your 40gr throw could be recorded as 4.53cc which is much quicker to come back to at a later date. The item is easy to swap out on an existing uniflow powder measure. This is a luxury item which saves time; the powder measure will function without it just fine.
6.) Some of these are luxury items whilst one is an essential, in my opinion. My bench is low when standing so I found that I needed to bend my knees to fully throw the charging handle. It was fine if I were sitting. I bought a 4" micro riser from Inline Fabrication which made the bench the perfect height. This mount also features a small rail out front which allows me to fit two small bins to the front which holds cases etc. for loading on the process. I also have fitted a case kicker system which kicks out a case when I'm lowering the ram and places it into one of the bins. The ergo roller handle replaces the standard ball handle, and the vertical displacement is much lower (since you are pushing more forward and leaving the handle to the work) which makes long loading sessions easier on the shoulder. The one item I consider worthwhile spending on is the improved primer ejections system. With the standard Rockchucker press sometimes an ejected primer will miss the chute and bound around on your work bench, on the floor or what not, but most importantly all the debris will clog up the press. Inline Fabraction make a 3D printed piece of plastic which replaces the RCBS spent primer tray and it is a much tighter fit to the ram. Spent primers will then flow down a piece of tubing which can be directed straight into the bin, no more mess!